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CPU performance
We have several devices of, er, note to compare against the Galaxy Note 4 with the Exynos 5433 SoC. The iPhone 6 Plus only has two cores, but those are relatively fast CPU cores of Apple's own custom design. Aside from the Note 4, the iPhone 5S, 6, and 6 Plus have the only other ARMv8-compatible cores in this comparison. The LG G3 and OnePlus One are both based on the Qualcomm Snapdragon 801 with quad Krait cores. The version of the Note 4 based on the Snapdragon 805 should be up to 20% faster than these devices. Finally, one of the more intriguing comparisons is Nvidia's Shield Tablet, which packs four Cortex-A15s at up to 2.2GHz. The Cortex-A15 is the direct architectural predecessor to the Cortex-A57, but aboard the Shield Tablet, those cores are operating within the larger power envelope of an 8" device.

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.

Memory bandwidth



The Note 4 with Exynos isn't off to a terribly impressive start in this synthetic test of memory bandwidth. The Exynos 5433 has been reported to have dual-channel 32-bit memory running at 825 MHz, or 1650 MT/s, which would yield 13.2 GB/s of peak bandwidth. The Note 4 doesn't come close to reaching that mark in Stream's copy test (and it's no faster in scale, add, or triad, which I've not reported above).

The Note 4's relatively weak showing could be the result of bumping up against a power management limit—directed tests sometimes do that—or it could be something else. Most modern CPUs max out their memory bandwidth by pairing a relatively large cache with a predictive pre-fetch mechanism that analyzes access patterns and pulls data from memory before it's needed. The Cortex-A57 cluster in the Note 4 may not be tuned as aggressively as its competition for whatever reason.

Geekbench
Geekbench runs natively on both iOS and Android, and it offers us a look at both single- and multi-threaded performance. You can click on the buttons below to toggle between the two sets of results.

The Note 4 performs well in the single-threaded tests, turning in the best score overall among the Android-based devices. Only Apple's ARMv8 custom cores are faster—and that depends on the test. In integer math, the Note 4 outperforms even the Cyclone core in the iPhone 5S. Only the iPhone 6 and 6 Plus are faster.

Interestingly, in these same integer tests, the quad Cortex-A57s in the Exynos 5433 substantially outperform the four Cortex-A15s in the Shield Tablet's Tegra K1 SoC, despite spotting them a 300MHz clock speed advantage. The gap closes almost entirely in the floating-point math tests, though.

Switch over to the multithreaded results, and the Exynos 5433 looks even stronger. The Note 4 takes the top spot in Geekbench overall and outright dominates the multi-core integer scores. With only two cores on tap, the 6-series iPhones fall well behind.

The AES encryption test illustrates the impact of tailored acceleration instructions built into the ARMv8 instruction set. The Exynos 5433 benefits from these instructions, as do Apple's newer custom cores.

Since the Exynos 5433 uses the global task scheduling version of big.LITTLE, we might be able to find some evidence of its four A53 cores assisting the four A57s. One indicator would be cases where the Note 4's multithreaded performance is more than four times its single-threaded performance.

Single-
threaded
Multi-
threaded
Difference
Geekbench overall 1280 4218 3.3x
Geekbench integer 1585 6101 3.8x
Geekbench floating point 1019 3841 3.8x
Geekbench AES encryption 818 4069 5.0x
Geekbench raytrace 1452 5585 3.8x

If the Note 4 is using more than four cores, the effect is fairly subtle. Only in certain sub-tests, like AES encryption, does the Note 4 achieve a speed-up of more than 4x with multiple threads. Hmm.

We might get some more insight by comparing Note 4's scaling to that of the quad-core Shield Tablet. Here are the overall results along with some hand-picked sub-tests that show the best scaling from one to many threads.

Single-
threaded
Multi-
threaded
Difference
Shield Tablet integer overall 1197 4303 3.6x
Note 4 integer overall 1573 5935 3.8x
Shield Tablet AES encryption 67 305 4.6x
Note 4 AES encryption 818 4069 5.0x
Shield Tablet SHA1 encryption 2108 8259 3.9x
Note 4 SHA1 encryption 4393 21792 5.0x
Shield Tablet JPEG compress 1322 5384 4.1x
Note 4 JPEG compress 1383 5866 4.2x

The Note 4 does scale slightly better than the Shield Tablet in Geekbench's overall index, but both are less than four times as fast. In certain sub-tests, the Note's multithreaded performance improves by more than 4x, but the Shield Tablet's does, too. Some other factor, like good locality in the tests' access patterns keeping the caches warm, could account for scaling beyond 4x.

If the Cortex-A53s in the Exynos 5433 are contributing to higher overall performance, it's awfully hard to tell by looking at these benchmark scores. The reality may be that the Exynos 5433 and its quad A57 cores are too power-constrained to allow those Cortex-A53s any meaningful thermal headroom. Devoting all of the juice to the A57s instead may be the best use of the SoC's power budget, anyhow.

Browser benchmarks




I used Google Chrome as the browser for all of the web-based benchmarks on the Android devices. That decision may have cost the Note 4 some performance in SunSpider and Kraken, if the Samsung browser has more extensive JavaScript optimization in it. Even so, the Note 4 performs relatively well.

Notice that the two top spots in SunSpider and Kraken are occupied by desktop CPUs. I sneaked those in just for fun. They have the benefit of much larger power envelopes.

BaseMark OS II


WebXprt






The rest of the CPU benchmark results are strangely inconclusive, in a way. The Note 4 easily outperforms the Snapdragon 801-based LG G3 in Basemark, just like it does in Geekbench, but the balance changes in WebXprt. There's no question the Exynos 5433 is a solid performer overall, but its position relative to the competition depends quite a bit on the workload in question.

That said, the contest with the iPhone 6 Plus looks to be pretty clear-cut. The iPhone is at or near the top of the stack in nearly every case. Apple's custom CPU core still gives it an edge, even though the Cortex-A57 helps to close the gap.