Apple’s iPhone 6 and 6 Plus smartphones reviewed

Apple’s iPhone has unquestionably shaken the foundation of the computing world since its introduction, and, like many folks, I’ve carried one in my pocket for years. Even so, we here at TR haven’t focused too much of our attention on smartphones. We’ve preferred instead to focus on larger computers, from tablets to laptops and, of course, hulking desktops with multiple teraflops of computing power. Thing is, smartphones keep maturing and advancing, thanks to huge profits being plowed back into their development. They’re becoming incredibly compelling and downright impossible to ignore.

Consider the iPhone 6 Plus my breaking point.

Apple has, at long last, caved to market pressure and given the people what they want: iPhones with larger screens, including one in the kinda-sorta ridiculously large “phablet” format. The move to bigger touchscreens is a transformative step in the smartphone’s evolution, in my view. Smartphones have long been incredibly useful computing devices of last resort, but they are becoming something more than that.

Screen size is only one reason for this shift. Apple’s latest iPhones have made substantial advancements in CPU and graphics performance, still and motion image capture, display quality and—blessedly—battery life. The eighth-generation iOS improves usability and offers new freedom for apps to interact with one another. And these phones have a robust array of sensors and wireless communication standards, one of which, near-field communication (NFC), enables a new payment service called Apple Pay. The bottom line is that premium smartphones now offer a distinctive computing experience that can’t easily be duplicated with any other sort of device.

None of this has happened in a vacuum, of course. Apple’s early lead in smartphone tech has been eroded by the ascendancy of Google’s Android OS and the phone makers deploying it. Choosing between premium smartphones these days can be daunting, difficult work. One good friend of mine, a life-long computing enthusiast and Mac owner, has been stuck in wrenching indecision between the new iPhones and the Android-based alternatives for weeks, and I can relate. With that difficulty in mind, we’ve decided to turn our full scrutiny toward a pair of smartphones for the first time. What better place to start than Apple’s iPhone 6 and 6 Plus?

The larger 4.7″ and 5.5″ displays are the most obvious enhancements in the new iPhones, but Apple has made progress on a host of fronts. The highlights include a brand-new A8 SoC with higher performance, support for the 802.11ac Wi-Fi networking standard, and an iSight camera whose eight-megapixel resolution belies substantial improvements.

Also, Apple has finally raised the flash storage capacity of the two higher-end models to 64GB and 128GB. Unfortunately, the bottom rung of the lineup remains at 16GB, which seems rather paltry in late 2014. I suppose the net effect of these changes is to make 64GB the point of entry into the iPhone 6 lineup for power users.

Another potential weakness in the spec sheet is Apple’s decision to hold steady at 1GB of main memory in the iPhone 6 and 6 Plus. Although iOS and Android admittedly use memory quite differently, many premium Android smartphones now ship with 2GB or even 3GB of RAM. Among iOS devices, only the iPad Air 2 has surpassed the 1GB mark.

Design and build quality

From left to right: The iPhone 5, 6, and 6 Plus

The new iPhone enclosures are noticeably taller and wider than the prior generation, but they retain Apple’s iconic design cues, including durable glass-and-aluminum construction. The build quality is up to Apple’s usual standard, with no apparent gaps, flex, or other imperfections. Our examples are clothed in the “space gray” color scheme.

The iPhone 6 (left) and 6 Plus (right)

The only two ports on these phones are a 3.5-mm headphone jack and Apple’s wonderfully reversible lighting connector. After using a Lighting connector and micro USB on a daily basis for the past couple of years, I’m unquestionably sold on Apple’s approach here.

The iPhone 6 and 6 Plus (left) and the iPhone 6 vs. 5 (right)

By the numbers, the 6 and 6 Plus are thinner than prior iPhones, but this is the first generation of Apple phones whose sapphire lens covers protrude from the back of their enclosures.

Except for the home button, all physical controls are on two sides of the case

The new phones’ volume controls and vibrate toggles are right where one would expect, but the sleep/wake button has migrated from the top edge of the case to the left edge, aping the placement used in many Android devices. This change is eminently sensible given the increased size of the enclosure. Leaving the button up top would make for an awkward reach, especially on the relatively gigantic 6 Plus.

One other change of note isn’t apparent in the pictures above. The iFixit teardowns have revealed internal rubber gaskets surrounding the buttons on these phones, likely improving their water resistance versus prior models.

About the size issue
I don’t think there’s any question Apple made the right move by introducing larger iPhones. After all, these devices are pocket computers first and foremost, not just phones, and with touch-based interfaces, screen real estate is at a premium. Typing, browsing the web, using apps, playing games—everything is easier and more comfortable on a larger display. If anything, this move comes a couple of years later than it should have.

The iPhone 6 Plus (left) dwarfs the regular iPhone 6 (right)

Fortunately, Apple has seriously committed to these larger form factors. With its 4.7″ screen, the iPhone 6 is easily roomier than the iPhone 5 and 5S—and the 5.5″ iPhone 6 Plus feels like a mini tablet.

For those of you wondering which one to get, I’ve spent quite a bit of time with both of the new iPhones, and I think the answer is clear. The iPhone 6 is undoubtedly the sane and proper size for a phone that will be carried on your person pretty much constantly. Practically speaking, it feels no bulkier than an iPhone 5 while stowed away in a pocket. When out of the pocket, the 6 fits well into one hand. Despite that infamous iPhone 5 commercial a couple of years ago, I can easily tap any spot on the screen with my thumb while holding the phone in the same hand. The iPhone 6’s size seems obvious and logical.

And the iPhone 6 Plus you see tested in this review, I confess, is the one I bought for my own personal use. I saw it in the store, with its big, bright display, and caved to the temptation of overcompensating for two years with my too-small iPhone 5.

Now that I’ve committed to it, I can tell you that the iPhone 6 Plus really is quite enormous. Even for a phablet, it’s relatively tall, in part due to the the large physical home button that most other phablets lack. If you’re a dude, this thing will test the depths of your front pants pocket. For you ladies, well, you can probably forget the pockets. You’ll want to store the 6 Plus in a purse, most likely. Having spent several weeks toting this massive slab around, I realize that I’ve made a terrible mistake.

….that I really, really enjoy. As soon as I pull it out to use, the 6 Plus magically transforms from an oversized pocket tumor into a wondrous convenience. Typing on it in portrait mode finally makes touchscreen keyboards seem sensible, and the roomy screen feels much less confining. Among other things, this device may just be the ideal e-reader.

The biggest wonder of all, though, isn’t the 6 Plus’s technology or design; it’s the fact that, somehow, it’s now become socially acceptable to carry a mini-tablet around in your pants. People even have complimentary things to say about how large your phone is. I’m not quite sure how that happened, but I’m not going to question it. As a card-carrying computer nerd, I’m just going to ride this wave quietly while it lasts.

I dunno how much any of that will help you pick the right size for you, but I do have one other impression to offer. Whichever model of iPhone 6 you choose, after you’ve spent a little time with it, older iPhones will feel like silly, miniature toys by comparison.

The A8 SoC
At the heart of the new iPhones beats a new system-on-a-chip (SoC), the Apple A8. The A8 is at least an incremental upgrade over the A7 SoC from the iPhone 5S, although Apple is fairly coy about the exact details of its silicon designs.

Outside of Apple’s own statements, the best sources of info on the A8 SoC are this teardown analysis by ChipWorks and Ryan Smith’s take on it. The A8 chip has been widely reported to be manufactured at TSMC on a 20-nm fabrication process, and the A8’s considerably smaller die size lends credibility to those reports.

We know that the A7 has two copies of Apple’s own custom CPU core, dubbed Cyclone. Cyclone is a high-IPC core compatible with the 64-bit ARMv8 instruction set. The A8 SoC in the iPhone 6 and 6 Plus also has dual cores, and those cores are clocked only 100MHz higher than in the A7 in the iPhone 5S. Indications point to these cores being a tweaked version of Cyclone. The size of the CPU cores on the die hasn’t dropped commensurately with expectations in light of the die shrink, so the cores themselves must contain more complex logic, larger structures, or both. These changes are likely intended to improve per-clock instruction throughput.

The locations of the the L2 SRAM arrays in the A8’s floorplan have changed from the A7, and Chipworks speculates that Apple may have moved to 1MB of dedicated L2 cache per core. However, the more probable reason for the change isn’t a size increase but increased modularity. Each core now appears to have its own “slice” of associated L2 cache, so that the cache size can scale up with the core count. Such an arrangement would make sense in light of the fact that the A8X SoC used in the iPad Air 2 has three CPU cores.

Another set of SRAM arrays on the chip is likely a last-level cache, probably 4MB in size and possibly shared not just between the CPU and GPU blocks but by the whole of the SoC. This LLC is also present in the A7.

That’s all good news, in my book. While many of its competitors have taken the path of increasing core counts in their latest SoCs, Apple has built one of the highest-throughput mobile CPU cores anywhere. We know even from big desktop PCs that the user experience is often dominated by the performance of one big, hairy thread that’s difficult to execute. Apple’s decision to pursue higher per-thread performance instead of expanding the core count seems like the smart course.

SoC and CPU performance
Comparing SoC performance across platforms isn’t easy, but we do have a handful of reasonably useful benchmarks we can employ. We’re spoiled by the extensive instrumentation and easy scripting of the PC platform, I suppose, but many of the tests below (and on the following pages) don’t do the work we’d prefer they did. For instance, many mobile benchmarks simply report synthetic scores without reference to anything concrete, like a rate of computation or the time to completion of a task. Where possible, we have reported the results below in concrete units, even if those aren’t the most commonly quoted numbers you might see elsewhere.

Also, mobile benchmarking is fraught with shenanigans related to power management policies. We’ve not yet mapped out this space well enough to effectively counter some of the benchmark detection efforts phone makers have been known to use. That said, all of the numbers we’ve reported are the median of at least three test runs, and we’ve discarded any major outliers from the pool of results.

We have several notable devices on hand to compare with the iPhone 6 and 6 Plus. Those include three prior generations of Apple offerings, the iPhone 5S through the iPhone 4. The OnePlus One and LG G3 are competing large-format Android phones, both based on Qualcomm’s Snapdragon 801 SoC with quad “Krait” custom CPU cores and Adreno 330 graphics.

Beyond phones, we have Nvidia’s Shield Tablet, based on a Tegra K1 GPU with quad Cortex-A15 CPU cores and Kepler-class graphics. This device is an 8″ tablet with a larger power envelope than a smartphone, but the architectural comparison should be interesting, with that caveat kept in mind. Also on hand is the Asus Memo Pad ME176C, a low-cost tablet based on Intel’s Atom “Bay Trail” Z3745 SoC; this SoC features quad “Silvermont” cores and Intel HD Graphics.

Many of you are probably hoping for comparisons against one or two other significant competitors in the high-end smartphone space. We don’t have those results below, but stay tuned.

Memory bandwidth

We don’t know the exact DRAM configuration of the new iPhones. Since they use LPDDR3, the channels are narrower than in desktop memories, either 16 or 32 bits wide. The Stream results suggest the possibility of dual 32-bit memory channels running at 1333 MT/s, if the SoC is squeezing out every last drop of bandwidth. There’s some warrant in the die images for the presence of dual SDRAM interfaces in the A8’s I/O ring.

We do know that the A8’s CPU cores are the only ones here that appear to reach the peak potential of the SoC’s memory subsystem in Stream’s copy test using a single software thread. Also, even with multiple threads, none of the other devices can match the peak transfer rates of the iPhone 6 and 6 Plus.

Geekbench
Geekbench runs natively on both iOS and Android, and it offers us a look at performance with just a single thread and with multiple threads. You can click on the button below to toggle between our single- and multi-threaded results.

Apple has carved out a substantial lead for itself in smartphone CPU performance, at least among the contenders we’ve tested. The A8 is far and away the fastest SoC here in single-threaded performance. What’s more, even though the A8 has only two cores on tap, its multithreaded performance is more than competitive. Only the Shield Tablet, with four Cortex-A15s in a larger power envelope, outperforms the A8 in Geekbench’s multithreaded tests.

The A8’s single-threaded CPU performance has risen by 16% overall in Geekbench, with the gains coming in both integer and floating-point math. As the table above illustrates, the performance improvements outstrip the increase in CPU clock frequency. The A8 may have a new dynamic frequency boost mode we don’t know about, but in all likelihood, its CPU cores have been tweaked for increased per-clock throughput.

Geekbench has a ton of component tests, but I’d like to call out one especially interesting result. The AES encryption test illustrates the impact of tailored acceleration instructions built into the ARMv8 instruction set. Apple’s A7 and A8 SoCs are the only beneficiaries among the devices we’ve tested, but one can expect to see a similar boost in this test for other ARMv8-compatible SoCs.

Obviously, the iPhones’ huge lead in this test is a bit unusual. I was concerned that the results from this component test would throw off Geekbench’s overall integer and composite scores. After a little noodling around in a spreadsheet, though, I’m satisfied. Turns out Geekbench uses a geometric mean to compute its overall indexes, so outlier scores shouldn’t have an outsized impact on the results.

Browser benchmarks

The new iPhones continue to perform well in these cross-platform, browser-based benchmarks. The closest competitors here, the L3 G3 and OnePlus One based on Qualcomm’s Snapdragon 801, are clearly outclassed.

Speaking of which, I’ve quietly slipped in some results from a couple of desktop processors, just to illustrate how close these mobile SoCs come to matching x86 CPUs with power envelopes nearly an order of magnitude higher. Remarkable, really.

BaseMark OS II

WebXprt

Intel has evangelized WebXprt pretty enthusiastically. We don’t always like it when a company backs a particular benchmark, but given Intel’s history there, I’m sure there’s nothing to worry about. Right?

Regardless, the new iPhones take the top spot in WepXprt’s overall index thanks to strong performance in each workload. However you slice it, really, the A8 SoC has some of the highest CPU performance of any mobile device we’ve tested.

Graphics
The A8 die shots show an integrated GPU with four “cores,” and each pair of GPU cores appears to share a major logic block between them. The most likely candidate for the new iPhone GPU, far and away, is the PowerVR GX6450 from Imagination Technologies. Apple has long relied on PowerVR GPUs for its iOS devices, and the GX6450 is a four-core product from the PowerVR Series6XT family based on the “Rogue XT” architecture.

The Rogue XT architecture is a bit unusual compared to most conventional GPUs because it’s built around a tile-based deferred rendering (TBDR) method. We’ve reviewed “tiler” GPUs of this sort before, but it’s been a while (unless, you know, there’s something Nvidia isn’t telling us). TBDR rejiggers the order of the traditional graphics pipeline in order to ensure that the GPU only spends its cycles shading and texturing pixels that will appear visible in the final frame being produced. In theory, at least, these GPUs ought to be very efficient with their resources. That’s probably why Imagination Technologies has been a big player in a mobile SoC world defined by strict constraints.

Imagination Technologies has been reasonably forthcoming about the guts of its graphics IP recently, so we have a fairly good idea how the various iPhone GPUs ought to stack up (although Apple may have modified some of that IP in ways we don’t know). I think we can trust the basic per-clock GPU throughput numbers above. The GPU clock speeds are easy enough to estimate by testing delivered performance, as we’ve done below, and working backward.

Apple has touted a substantial graphics performance increase for the new iPhones, and such things are usually achieved by making the GPU wider. You’ll notice in the table above that the area of the A8’s die dedicated to the GPU has only dropped by a few square millimeters, in spite of the process shrink from 28 to 20 nm. Clearly, the amount of GPU logic present has grown. Curiously, though, the peak shader arithmetic, texturing, and pixel fill figures haven’t increased from the A7.

Chalk up that anomaly to the direction Imagination Technologies took with its PowerVR Series6XT. The PowerVR GX6450 has many of the same theoretical peak rates as the G6430 before it, but there’s more going on under the covers. Although the fp32 math rate is the same, the Rogue XT shader core can deliver 25% more fp16 flops than its predecessors. The on-chip SRAM pools for tile buffers, the register file, and the caches have grown in size so that the existing graphics units can be more fully utilized. Rogue XT also adds support for the ASTC texture compression algorithm first developed by ARM. Thanks to these changes, the GX6540 should improve delivered performance even without an increase in peak rates. (For those interested in the gory details of the Rogue shader units, I’ve written a little about them here.)

Directed tests

These first two tests stress key graphics rates for texturing and shading. The A8 more or less keeps pace with the Adreno 330 GPU in the L3 G3 and OnePlus One in terms of texturing throughput, but the new iPhones fall behind in a directed test of shader arithmetic. (I get a kick out of writing about Qualcomm’s GPUs, since “Adreno” is an anagram for Radeon, revealing its roots at ATI.)

The Tegra K1 in the Shield tablet is both figuratively and literally in another class.

Alpha blending is more of a classic graphics sort of thing to do, and in this workload, the new iPhones suddenly look to be more competitive.

As I understand it, this benchmark attempts to measure driver overhead by issuing a draw call, changing state, and doing it again, over and over. Performance in this test may end up being gated by CPU throughput as much as anything else. That fact could, at least in part, help explain the iPhones’ big lead here. Driver overhead is a significant part of the overall performance picture in 3D gaming, so this result is relevant regardless of the primary constraint involved.

Off-screen gaming
All three of these tests are rendered off-screen at a common resolution, so they’re our best bet for cross-device GPU comparisons. They’re also more complete benchmarks than the directed tests above, since they involve rendering a real scene that could plausibly come from a mobile 3D game. The older iPhones can’t run GFXBench’s “Manhattan” test because it requires OpenGL ES 3.0 compliance.

As soon as it gets its claws into this sort of workload, the A8’s GPU looks quite a bit stronger than it does in synthetic tests of ALU and texturing rates. The delivered performance and efficiency of the GPU in the new iPhones is quite good—and according to GFXBench, at least, the GX6450 is indeed a substantial step up from the G6430 in the iPhone 5S.

The iPhone 4, uh, was good for its era, but I’m not waiting for those benchmarks to finish ever again.

Native device resolution gaming

Devices with higher-resolutions displays will have to push more pixels in order to deliver the same frame rendering times as their lower-res competition. The tests above give us a look at how these systems fare when asked to light up all of their pixels. Although the 6 Plus’s GPU appears to be clocked somewhat faster than the iPhone 6’s, it extra juice isn’t enough to make up entirely for 6 Plus’s higher display resolution. In one of the two tests, at least, the 6 Plus is faster than the iPhone 5S.

More importantly, my 6 Plus certainly runs Infinity Blade III smoothly.

The iOS version of Basemark X runs on-screen and off-screen tests and then spits out a single, composite score, unfortunately. I wish we could break out the component tests, especially since this benchmark walks through a nice-looking scene rendered using the popular Unity game engine.

Image quality
One other feature of Basemark X is an intriguing quantitative test of graphics image quality.

Real-time graphics is strange because there’s not always one “right” answer about the color of a rendered pixel. Filtering methods and degrees of mathematical precision vary, since GPU makers take different shortcuts to trade off image quality against performance.

Basemark X attempts to quantify the fidelity of a GPU’s output by comparing it to some ideal—in this case, I believe the reference renderer is a desktop-class graphics chip. That’s a fair standard, since desktop chips these days produce something close to ideal imagery. The higher the signal-to-noise ratio reported, the closer these mobile GPU come to matching the reference image.

Frustratingly, a couple of the devices refused to run the quality test with “out of memory” errors. Among those that did run the test, the Tegra K1 in the Shield tablet comes out on top. The other mobile GPUs are pretty closely bunched together after that. I suspect the Tegra K1’s score is the same in the regular and high-precision versions of the test because its GPU always renders everything using fp32 precision internally, even if the application doesn’t request high precision.

The flip side of that coin is what happens with the PowerVR and Adreno GPUs in the high-precision test. They all hit a ceiling at about the same place, well below the Shield Tablet’s score, even though their shader ALUs are capable of fp32 precision when requested. I suspect the limitation here isn’t in the shader ALUs, but in other graphics-focused hardware, interpolators and such, whose internal precision may not be up to snuff.

This limitation isn’t a problem for mobile graphics in its current state. Both the iPhones and the Qualcomm-based devices produce rich visuals without any obvious artifacts in today’s games. But mobile GPUs may need to gain more consistent precision, like desktop GPUs did in the DX11 generation, going forward. Games may require added precision as developers layer on ever more complex effects, and GPU computing applications will probably require it, as well.

Storage
The selection of cross-platform storage tests out there isn’t spectacular. PassMark has some basic transfer rate tests, and Basemark has a test painfully labeled “memory” that seems to test storage somehow.

What these tests seem to reveal is decent basic storage performance for the new iPhones, with one curious exception: the iPhone 6 Plus is substantially slower than the iPhone 6, particularly in the PassMark write test. This difference could be related to the fact that our iPhone 6 Plus is a 64GB model, while the iPhone 6 has 128GB of flash. Or it could be related to the rumors that Apple has switched to TLC NAND, which is slower to write data, in at least some new iPhone models.

Neither of those explanations would fully account for the write speed difference entirely, though. Another possibility is that Apple could be using a portion of the NAND array as a fast cache by storing only one bit per cell in it, while the rest of the drive stores three bits per cell in a TLC configuration. Some desktop SSDs do this sort of thing, and the delta between write speeds in the two modes can be large. (The 840 EVO 120GB‘s SLC writes are rated for 410MB/s, while TLC writes happen at 140MB/s.)

If Apple is using an SLC-TLC caching arrangement, that could explain the numbers above. The size of the single-bit NAND cache is probably larger in 128GB configs. It’s possible PassMark overruns the SLC cache in the 64GB config but not in the 128GB one. Also, if the new iPhones do use a one-bit NAND cache, then wow, Apple’s storage management is much more sophisticated than I’d expected.

Whatever the case is, it’s hard to tell. iFixit’s teardowns reveal the iPhone 6 using SanDisk flash, while the 6 Plus uses NAND from Hynix, but both of those parts are 128Gb (16GB) models. Furthermore, Hynix’s data sheet lists the part number in the 6 Plus as “E2NAND3.0” without revealing whether it’s MLC or TLC NAND. And our software tools are mighty limited on iOS.

Regardless, the 6 Plus 64GB doesn’t feel noticeably slower than the iPhone 6 128GB in regular use, even in write-intensive tasks like burst photography or video capture. Both phones are fast and fluid in workloads of that nature.

Battery life
We tested battery life in four different scenarios. In each case, the phones’ display brightness was set to 180 cd/m² before starting, and display auto-brightness features were disabled. Our workload for the web surfing tests was TR Browserbench. The video test involved looped playback of a 1080p video recorded on one of the phones, and our gaming workload was the Unreal Engine-based Epic Citadel demo.

I resisted including our older iPhones in these tests because their batteries have considerable wear and tear by now. That narrows the field somewhat.

Owners of older iPhones will instantly recognize how much of an improvement these results are simply by looking at the number of hours involved. For web browsing and video playback, the new iPhones have essentially all-day battery life. Interestingly, our measured results track pretty closely with Apple’s own estimates. For instance, the firm claims “up to 11 hours” of Wi-Fi browsing time for the iPhone 6 and “up to 12 hours” for the 6 Plus.

The real torture test is the gaming workload, where the SoC is working hard throughout. Here, the OnePlus One’s run time nosedives to just 2.6 hours, and the iPhone 6 isn’t far behind at 3.7 hours. The 6 Plus’s larger battery makes it less fragile; the 6 Plus manages over six hours in the gaming test.

These results generally square with my own experience. I’ve spent weeks using the iPhone 6 Plus as my primary phone, and by habit, I charge it each night. Even with a silly amount of use throughout the day, the 6 Plus’s battery meter rarely drops below 40%. That’s a massive upgrade from my iPhone 5, which I had to nurse through busy days with periodic charging sessions. I couldn’t be happier to see progress on this front, which has been a sore spot in recent years as phones have grown thinner and lighter.

I’m also pleased to see that Apple has added a battery usage meter in Settings that allows the user to see which apps are sucking up battery power. I was surprised to learn, for example, that Google Hangouts was the cause of some battery life woes on my iPhone 5. As newer versions of iOS grant apps more freedom to work in the background and interact, tools like that become more valuable.

Display
The displays in the iPhone 6 and 6 Plus are obviously larger than their predecessors, with higher resolutions and—in the case of the 6 Plus—higher pixel densities, as well. They’re still LCDs based on in-plane switching (IPS) technology, and their pixel counts and densities are at least in the ballpark with leading Android phones, though some of those products sport even higher resolutions.

Here’s a look at the iPhone 6 Plus up close. You can move your mouse over the thumbnail to see a pop-up window with a close-up photograph. Mobile users, just tap the thumbnail to load the full image and pinch-zoom to your heart’s content.

That’s a ton of detail. I suspect most folks won’t be able to pick out individual pixels with the naked eye.

The most notable changes in the new iPhone displays, though, have to do with pixel quality rather than pixel count. Contrast ratios, or the differences between dark and bright pixels, have nearly doubled compared to the prior generation. The new displays also adopt dual-domain pixels, in which subpixel alignments are skewed slightly in interleaved rows. The effect of this arrangement should be better off-angle viewing with less color shift.

Those explanations sound fine in theory, but in person, the impact is dramatic. Under the bright lights at the Apple store, I asked my son to hold his shiny new OnePlus One up next to the 6 Plus for comparison. Then I felt sorry for the boy. The brights are so much brighter and darks darker on the 6 Plus that it’s kind of silly. (The iPhone 6’s display is similar, just a bit smaller.) The 6 Plus was unquestionably the finest mobile display I’d ever seen—until I got a glimpse of the OLED display in the Galaxy Note 4. Man, the competition in this space is bonkers.

We can easily measure the improvement in contrast with a colorimeter.

Although the new iPhones’ white levels are similar to the iPhone 5’s, the iPhone 6 and 6 Plus displays achieve deeper black levels at the same time.

All of these phones are capable of displaying essentially the entirety of the sRGB color gamut, as advertised.

Both of the new iPhones come out of the box with a color temperature closer to the 6500K standard than my old iPhone 5. By contrast, the OnePlus One registers a relatively cool ~8700K average temperature, which is pretty far from expectations.

Color accuracy has improved compared to the iPhone 5, as well, with lower overall delta-E for the new displays and no major weaknesses.

The iPhone 6 Plus (left) and 6 (right) from above and at an angle

True to their billing, the new iPhone displays also excel at off-angle viewing, with relatively little loss of contrast and almost no perceptible color shift. I’ve never seen anything quite like it.

The iSight camera
The pixel resolution of Apple’s iSight cameras has stayed steady over multiple generations. Rather than chasing megapixels, Apple has worked to improve image quality in other dimensions. The iPhone 6 and 6 Plus continue that trajectory.

Both of the new cameras have a five-element lens with a wide f/2.2 aperture, and the pixel size on the sensors works out to 1.5 microns.

The new iPhone cameras include a feature that Apple calls Focus Pixels but is more broadly known as phase-detection autofocus. Phase detection is a complex autofocus technique that’s traditionally been confined to DSLR cameras, but Samsung and now Apple have brought it into smartphones. This technique promises to be quicker than conventional contrast-based autofocus, particularly in low light.

Another feature that has migrated from higher-end cameras is optical image stabilization, which is exclusive to the iPhone 6 Plus. Optical stabilization can dramatically improve focus in hand-held shots, especially in low-light conditions where longer exposures are required.

The shooting experience on the new iPhones is quite good—in some ways, even better than with an expensive DSLR. The autofocus mechanism is indeed uncommonly quick. Even in low light, it zeroes in on subjects in under a second, with minimal to-and-fro “hunting” once it gets close to the proper depth. Of course, the iOS camera app only offers limited tuning options for the knowledgeable photographer. The app provides a slider to control the brightness of the exposure in real time—a welcome provision—and the flash mode can be tweaked, but that’s about it.

Fortunately, most of its automatic choices are sensible. The software’s high-dynamic-range (HDR) shooting mode can be disabled or enabled, as in the past, but it now defaults to an Auto mode where the software decides when to employ it. The burst shooting mode carries over from the iPhone 5S and remains incredibly useful: simply hold down on the exposure button to capture a series of shots at a rate of 10 photos per second. One may then pick a favorite from the group later, although the camera app seems to do a good job of selecting the image with the sharpest focus on its own. And the automatic white balance algorithm in the new iPhones seems to be outstandingly accurate.

As in most other smartphones, the iPhone camera automatically applies lens correction and some amount of noise reduction and sharpening to the final images. Apple’s software isn’t too heavy-handed on this front, thank goodness.

The sample shots
I took a ton of pictures for the sake of this review, including some attempts at ISO reference patterns and home-brewed “test scenes” with a quasi-intentional jumble of objects. I discovered that getting the proper shot in some of those cases with a smartphone is prohibitively difficult. Also, many of those pictures didn’t do a very good job of illustrating the differences between the cameras in question. In the end, I wound up choosing a series of sample shots, one in outdoor light and several indoors, in order to demonstrate the sort of results you can expect. The Javascript zoom tool below will show you every pixel as you mouse over the thumbnails (or you can click/tap on each image to load the original in a browser tab).

I’m reasonably satisfied that the shots below do most of the work we need, but this setup does have some limitations. For one, I tried to select the best exposures from each camera for the samples below, and I used burst mode to shoot them when possible. As a result, you can’t know from looking at the examples how much easier it was to get clear, sharply focused shots on the iPhone 6 Plus with optical IS. One can usually achieve similar results on the iPhone 6 without optical stabilization, but not nearly as consistently.

Also, my sense is that our two viewing modes—a tiny thumbnail and a super-zoomed 1:1 pixel window—may obscure the true differences between these pictures as one would typically view them. All of the low-light shots look noisy when zoomed, but there’s a big difference between the best and worst images when viewed in full-screen mode on my 30″ monitor. To see what I mean, try opening the Santa pictures below from the iPhone 6 Plus and the OnePlus One in full-screen browser windows. The difference is more dramatic than one might otherwise think.

Outdoor scene
This shot of my backyard is kind of depressing, but it captures the look of winter in suburban Missouri, I guess. The best way to compare quality here is to focus on specific objects in the scene, I think.

For instance, my neighbors’ satellite dish (on the left) shows a clear progression in sharpness from the iPhone 5 through the 6 Plus. The OnePlus One’s 13-megapixel sensor doesn’t capture colors accurately, but it does resolve detail a bit better in outdoor light. The text on the “DirectTV” logo is only legible in the shot from the OnePlus.

iPhone 5:

iPhone 6:

iPhone 6 Plus:

OnePlus One:

Sample scene: Santa
This is my favorite sample scene, since it’s a challenging low-light setting with a complex subject. Even with burst mode at my command, I struggled to get perfect focus on the iPhone 6. If you look at the star on top of the Christmas tree, for example, you’ll see a bit of ghosting. With optical IS, getting the right focus on the 6 Plus was much easier.

Also, notice how much noisier the iPhone 5 shot is compared to those from the newer iPhones. Meanwhile, the image captured by the OnePlus One looks smeary and inferior, even compared to the iPhone 5.

iPhone 5:

iPhone 6:

iPhone 6 Plus:

OnePlus One:

Sample scene: Edinburgh
For kicks, I shot each of our sample scenes with my Canon DSLR as well as the phones. The differences in the depth of the focal plane and other things made the DSLR’s shots barely comparable. The thing that stood out most in this scene, though, was the crazy amount of pincushioning, caused by lens barrel distortion, the DSLR photo contained. Meanwhile, the phone cameras correct for that effect computationally, so that the picture frame is shaped pretty much as it should be.

iPhone 5:

iPhone 6:

iPhone 6 Plus:

OnePlus One:

Video

The iSight camera has added two new video modes to its arsenal: 1080p recording at 60 frames per second, and 720p recording in slow-motion at 240 FPS. This last mode builds on the 120-FPS slow-mo mode in the iPhone 5S.

We have some examples of recorded video from each phone below. Of course, YouTube’s crazy compression has done some violence to the quality of the video produced by each device, but these examples should serve to illustrate a couple of things. As with the stills, the color is more saturated and correct on the iPhones than on the OnePlus One. Also, the iPhone 6 and 6 Plus use algorithmic stabilization to reduce camera shake. These videos were recorded handheld, with me walking around on concrete, and the smoother camera tracking on the new iPhones is readily apparent. If there is some additional benefit from the optical IS capability in the 6 Plus versus the iPhone 6, I’m not seeing it here.

iPhone 5:

iPhone 6:

iPhone 6 Plus:

OnePlus One:

If an iPhone 6 owner ever films a sasquatch, I expect nice, smooth camera movement to put any controversy to rest.

Slow-motion video
The slow-mo recording feature of the new iPhones is near and dear to my heart, simply because I want to use it as a professional tool. I decided to try it out exactly as I’d use it: to record 3D gaming animation on a 4K G-Sync monitor with a 60Hz peak refresh rate. I mounted the 6 Plus on a tripod with some double-sided tape and gave it a go.

Man, I wish my DSLR would do that. I think it’s safe to say I can retire the Casio camera that I bought specifically for high-speed recording. The 6 Plus is a better tool for that job—not to mention that recording slow-mo videos of, say, Fourth of July fireworks or kids playing with bubbles is just a lot of fun.

What’s not fun is figuring out how to export a slow-mo video from the iPhone that will play back at the proper speed on other systems. A straight file copy doesn’t work. I had to import the video into iMovie, create a project, add the movie to it, and export. I’d really like to see this quirk fixed in a software update, so that copying 120/240-FPS videos off of the phone in the proper format is easier.

Networking
The Qualcomm MDM9625M modem in the new iPhones is a 28-nm chip that supports the Category 4 LTE standard, with download speeds up to 150 Mbps and uploads as fast as 50 Mbps. That’s an upgrade over the Category 3 modems in the 5-series iPhones, whose download speeds top out at 100 Mbps. The MDM9625M also supports carrier aggregation, essentially the use of multiple wireless channels simultaneously, in order to increase throughput. That said, Qualcomm is already shipping a Category 6 modem capable of 300 Mbps transfer rates, so the MDM9625M is arguably a conservative choice.

Also new is support for the 802.11ac Wi-Fi standard, which can improve transfer rates on local wireless networks. Apple says the 802.11ac implementation in the new iPhones can be as much as three times faster than 802.11n.

Going into this review, I had big plans to measure network transfer rates in order to quantify the impact of these upgrades. I grabbed an Asus RT-AC87U router, and I sunk a ton of time into testing transfer rates over Wi-Fi and LTE from multiple locations. Unfortunately, my results weren’t anything worthy of publication. There was way too much variance in transfer rates from one test to the next, enough that it overwhelmed any differences between the phones. I may take another crack at Wi-Fi transfer testing in the future, using a different approach, but for now, we’ll have to do without.

For what it’s worth, practically speaking, I’ve found the new iPhones to offer solid all-around network performance. Their Wi-Fi is more robust than the two other devices I use regularly at home, a Nexus 7 and a Shield Tablet. Each of those tablets disconnects intermittently in a couple of well-known dead spots, but the iPhones generally do not.

Touch ID and Apple Pay
Like the iPhone 5S, the 6-series iPhones include a Touch ID fingerprint reader beneath the home button as a means of biometric identification. Surprisingly, this reader works well enough that I use it regularly in place of entering a four-digit PIN. It’s actually faster than tapping in a code most of the time. Touch ID struggles in certain conditions, like if your fingers are wet, but overall, it’s a win for convenience.

As you may have heard, Apple has built near-field communication (NFC) capabilities into the new iPhones alongside Touch ID. These two features combine to function as an authentication mechanism for the firm’s retail payment system, Apple Pay. Apple has persuaded a slew of banks and retailers to participate in the Apple Pay system, and many stores are already accepting NFC payments.

I decided to try it out, you know, for science. Apple Pay works slickly enough to be a little disconcerting, given that the technology’s purpose is to separate you from your money. The first step is adding a credit card from a participating bank, which can be accomplished by pointing the iPhone camera at said card. The Passbook app uses optical character recognition to retrieve your credit card number, and you’re good to go. Then, instead of swiping a card, you just hold the phone up to a supporting payment terminal and scan your thumbprint via Touch ID in order to complete a transaction.

I successfully purchased a Quarter Pounder with Cheese via Apple Pay, but only after flubbing the first attempt and having to start over. The Passbook interface for multiple credit cards is a little confusing, and as a result, I later realized that I’d charged my lunch on the wrong card.

Man, I was hoping to expense that.

My next attempt, buying poster board at Walgreens, went off without a hitch—and boy, do I lead an exciting life.

There is some drama unfolding right now over competing NFC payment standards, and who knows where it will all lead. Regardless, I expect to keep using Apple Pay where available. I like the fact that there’s a measure of biometric security involved, and I appreciate the way the Passbook app tracks and notifies me of charges made to my cards.

The multitasking issue
Generally, the new iPhones provide a fluid and compelling user experience, for reasons that our battery of benchmarks and empirical tests have illuminated. In the midst of all the goodness, there is one pain point I’ve noticed in my daily use of the iPhone 6 Plus. It has to do with multitasking.

I’m an inveterate multitasker. If I’m chilling out on the couch for the evening, I usually have five to seven apps that I keep active, and I switch between them pretty frequently. I’ve found that my Nexus 7 2013 with 2GB of RAM handles this sort of use well. Switching between apps is quick and seamless. Many high-end Android phones now come with 3GB of RAM, which should mean even less friction during multitasking.

Meanwhile, most iOS devices, including the iPhone 6 and 6 Plus, only have 1GB of RAM. Now, that’s not necessarily a problem since iOS uses memory and handles multitasking differently from other operating systems. iOS can be very efficient with RAM, but it sometimes requires extra waiting when switching between apps.

iOS “hides” task-switching latency by taking a screenshot of the app’s last state, making a “card” representation of the app, and moving that card around in UI animations that slide, shrink, and so on. When you return to an application after being away, iOS fades from the dated screenshot to the current app screen. Oftentimes, this transition happens seamlessly, and the app’s return to the foreground seems instant. Sometimes, though, the app has been ejected from RAM and must reload itself before continuing. When that happens, everything kind of grinds to a halt for a few seconds.

To be fair, this sort of thing can also occur on Android, but I’ve noticed that it happens more often in recent iOS devices than in recent Android-based ones. Honestly, it’s not that big of a deal, but it was a concern for me when deciding which phone to purchase for myself. Ultimately, I decided to go with the 6 Plus on the strength of my experience with iOS 8 on my old iPhone 5. Cycling through my usual suite of apps on it is usually pretty snappy.

Having used the 6 Plus for a while, though, I think perhaps it’s paying a bit of a tax for running 64-bit executables and rendering to a higher-resolution display. The video above illustrates the issue. For the first 60 seconds or so, I’m able to switch between apps quickly without any delays. After that, things go a bit sideways, and several of the same apps decide to reload themselves. Those reloads happen relatively quickly because the 6 Plus is based on fast hardware, but there’s no substitute for having the running app waiting in memory.

Perhaps the 6 Plus reloads apps more often because I’m using it more heavily, or perhaps the apps themselves are misbehaving. Whatever the case, the performance of the iPhone 6 and 6 Plus is fragile in this way. I think that’s a notable downside of an otherwise stellar product.

If this problem is a consequence of Apple’s decision to limit the new iPhones to 1GB of RAM, that’s unfortunate. Throwing another gig of RAM into a phone with this sort of price tag is surely feasible. (As I’ve noted, Apple has already moved to 2GB in the iPad Air 2.) Also, there’s some notable history here. Older iOS devices have struggled to perform well or to serve the entire feature set of newer OS revisions in part because of memory capacity limits. Knowing that makes me worry a bit about future iOS revisions squeezing into these phones.

A word about Apple’s cases
You really should keep a new iPhone in a case, particularly because cracked glass on an in-cell touch display can be expensive to replace. Initially, I bought a third-party case for my phone, one of the highest rated cases on Amazon, since I’m cheap and it was, too. Once installed, the thing added a bunch of bulk to the 6 Plus, which is a bad proposition.

Apple’s leather case for the iPhone 6 Plus (left) and silicone case for the iPhone 6 (right)

I’ve since gotten my hands on Apple’s cases, and yeah, they’re worth the price of admission. The leather case fits the iPhone 6 Plus like a . . . well-worn cliche. I mean, the leather is both soft and supple. I enjoy the rich feel of the soft cowhide covering, but it terrifies me a little, since I’ll probably ruin it. The silicone case is more utilitarian and could probably withstand a cougar attack without showing any wear. I doubt it would survive some alone time with my two-year-old, but durability always has its limits.

The front edges of each case protrude above the surface of the phone’s glass screen just enough to offer a measure of drop protection, yet neither one adds a millimeter of unnecessary bulk. I’m sure there will be decent third-party cases that achieve a similar balance, but the Apple cases set an awfully high bar.

Conclusions
The iPhone 6 and 6 Plus improve on their predecessors in nearly every major respect, from CPU and graphics performance to display and camera quality, networking speeds, battery life, and more. These elements come together to provide an experience that feels like a considerable upgrade over prior generations of iPhones. Apple has poured a ton of effort into ensuring that folks on an every-other-year upgrade plan will have a compelling reason to pull the trigger each time. I’d say Apple has more than met that goal this time around.

What’s more, Apple has measurably advanced the state of the art in many areas—like mobile SoC design, display quality, and camera capability—in order to build a better solution. The extent of the improvement in CPU and graphics performance from the iPhone 4 to the iPhone 6 is dizzying. If this trajectory continues for several more generations, mobile SoCs could match the performance of today’s fastest desktop systems.

The competitors we put up against the new iPhones, including older iPhones and the poor OnePlus One, were easily outclassed by Apple’s latest. That’s true in spite of the fact that the OnePlus, for instance, looks pretty strong on paper—with quad CPU cores, the same display dimensions and resolution, and more megapixels in its camera sensor. Spec sheets aren’t everything, folks. That said, the OnePlus One costs about half what the iPhone 6 does. The new iPhones face more formidable competition not represented in the preceding pages. In the phablet space, the iPhone 6 Plus has to tangle with Samsung’s excellent Galaxy Note 4 and Google’s brand-new Nexus 6. Again, stay tuned on that front.

One of the big sticking points for most folks choosing a high-end smartphone these days is a preference for a particular mobile OS. Android has been in a good place for a while, and I have to admit, I initially had some trepidation about choosing another iOS-based phone. Using iOS 8 on an iPhone 6 Plus has assuaged many of my concerns. Apple has closed the gap in areas like notifications and cross-app communication. Also, iOS 8 gives users quite a bit more freedom in moving data and documents around. Meanwhile, oddly enough, the Lollipop re-skin has given Android a look and feel that pretty closely resembles iOS 8. In many respects, the user experiences delivered by the two dominant mobile operating systems are closer together than ever.

Then again, Android Lollipop has only arrived on select devices, and it may not make it into some of the iPhone’s closest competitors for a good while yet. Apple’s integration of its own software and hardware remains one of its distinctive strengths, and the iPhone 6 and 6 Plus are awfully strong testaments to the power of that approach.

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