SanDisk’s Extreme Portable 1 TB SSD reviewed

Howdy, gerbils. Nvidia and its legion of board partners may doing their best to distract you with some newfangled foolishness, but we all know the real reason you’re here: solid-state storage. In particular, the kind you can put in your pocket.

Last year we reviewed external SSDs from Adata and Samsung and found them quite delightful. Manufacturers may go overboard with romanticized visions of surfers and mountain climbers pursuing their passions while drives dangle perilously from board shorts and carabiners, but the fact remains that these brands are very good at putting together potent portables in compact and attractive form factors. Anyone weary of the languid transfer speeds and shoddy construction of the average thumb drive would be well served to splurge on a portable SSD.

On today’s menu is SanDisk’s Extreme Portable 1 TB, the company’s latest ruggedized external. Have a look.

The Extreme Portable is a smart-looking 2″ x 3.8″ x 0.4″ (49.5 x 96.5 x 8.8 mm) slab with gently rounded corners and a red-on-black motif. Though at only 1.37 ounces the drive is feather-light in the hand, the grippiness of its textured plastic gives it a satisfying, premium feel. The fancy enclosure is good for an IP55 rating. IP55 translates to some resistance to dust and fairly robust protection from water sprays, although it doesn’t protect against outright submersion. The Extreme Portable  supports USB 3.1 Gen 2 and its 10-Gbps transfer rates over the bundled Type-C cable. SanDisk thoughtfully includes a Type-C to Type-A adapter as well, for those of us still rocking machines from yesteryear.

After some head-scratching I managed to prise off the top and peer into the innards, only to be greeted by a PCB completely swathed in black tape. Some cautious poking and scratching led me to two realizations. First, that tape disguises a copper film layer, presumably for heat-dissipation purposes. Second, that there was no way I’d be able to cleanly remove all the layers of wrapping for worthwhile internal photos. You’ll have to do without those this time around. But since SanDisk has kept mum about the Extreme Portable’s composite parts, I peeled away just enough of a corner to discern what the important bits are.

The controller is Marvell’s 88SS1074, which we’ve seen before in Crucial’s MX300. The NAND is the SanDisk-Toshiba partnership’s now-ubiquitous 64-layer BiCS TLC flash, which recently dazzled us in the WD Black NVMe. That combination means that the Extreme Portable is essentially a WD Blue M.2 strapped to a USB bridge controller and and packaged up nicely.

The intrepid Extreme Portable is available for $270 at Newegg for the 1-TB model we tested. SanDisk also offers the drive in capacities of 250 GB, 500 GB, and 2 TB for those who need more or less NAND. Apart from the drive itself, your money buys you a three year warranty and access to SanDisk’s Secure Access, a barebones-but-functional utility that comes preloaded on the drive and is available online. As you might have guessed, Secure Access grants access to the drive’s 128-bit AES encryption features.

Before settling in to testing, it would be remiss to not link SanDisk’s marketing video. It’s less over-the-top than some we’ve seen, depicting a relatively tame and plausible use case: transferring photos off of a camera while on a hike. Enjoy the soothing spa music.

Now, on to the testing.


IOMeter — Sequential and random performance

We skipped IOMeter in our previous coverage of portables, but since we had to collect a fresh set of data on the latest test rig anyway, we decided to throw our sequential and random tests at the drives as well.

IOMeter fuels much of our latest storage test suite, including our sequential and random I/O tests. These tests are run across the full capacity of the drive at two queue depths. The QD1 tests simulate a single thread, while the QD4 results emulate a more demanding desktop workload. For perspective, 87% of the requests in our old DriveBench 2.0 trace of real-world desktop activity have a queue depth of four or less. Clicking the buttons below the graphs switches between results charted at the different queue depths. Our sequential tests use a relatively large 128-KB block size.

The Extreme Portable beats Samsung’s speedy T5 at QD1 and matches it at QD4. You’ll notice we’re using the same Intel X25-M G2 that we use in our internal SSD reviews as a baseline here. Turns out modern USB 3.1 Gen 2 externals are more than fast enough to match up to crusty old SATA 3 Gbps drives.

The T5 enjoys a small lead over the Extreme Portable in the random response time domain, but the SanDisk is plenty peppy regardless.

The SanDisk started out strong in our IOMeter synthetics, but it’s real-world file transfers that really interest us when it comes to external drives. Time to turn to RoboBench.


TR RoboBench — Real-world transfers

RoboBench trades synthetic tests with random data for real-world transfers with a range of file types. Developed by our in-house coder, Bruno “morphine” Ferreira, this benchmark relies on the multi-threaded robocopy command build into Windows. We copy files to and from a wicked-fast RAM disk to measure read and write performance. We also cut the RAM disk out of the loop for a copy test that transfers the files to a different location on the SSD.

Robocopy uses eight threads by default, and we’ve also run it with a single thread. Our results are split between two file sets, whose vital statistics are detailed below. The compressibility percentage is based on the size of the file set after it’s been crunched by 7-Zip.

  Number of files Average file size Total size Compressibility
Media 459 21.4 MB 9.58 GB 0.8%
Work 84,652 48.0 KB 3.87 GB 59%

RoboBench’s write and copy tests run after the drives have been put into a simulated used state with 30 minutes of 4KB random writes. The pre-conditioning process is scripted, as is the rest of the test, ensuring that drives have the same amount of time to recover.

The media set is made up of large movie files, high-bitrate MP3s, and 18-megapixel RAW and JPG images. There are only a few hundred files in total, and the data set isn’t amenable to compression. The work set comprises loads of TR files, including documents, spreadsheets, and web-optimized images. It also includes a stack of programming-related files associated with our old Mozilla compiling test and the Visual Studio test on the next page. The average file size is measured in kilobytes rather than megabytes, and the files are mostly compressible.

Let’s take a look at the media set first. The buttons switch between read, write, and copy results.

Our three USB 3.1 Gen 2 drives are within striking distance of each other in the media set. The Extreme Portable is generally as fast as the T5 except when it comes to the copy results, where it falls behind a bit. The work set will likely smooth out this difference, but we’ll see.

The more random nature of the work file set takes a big toll on all of the USB drives’ speeds, especially when it comes to writing and copying. Suddenly the X25 doesn’t look quite so decrepit. It’s a back-and-forth exchange among the three external drives here, and none of them particularly stand out.

SanDisk’s Extreme Portable SSD gave us the gratifyingly high transfer speeds we were looking for. It excels at portable file-slinging, particularly when the workload is mostly sequential. Happily, that’s exactly the sort of use case these drives are intended for. The next page breaks down our test methods, or you can skip that boring stuff and jump to the conclusion.


Test notes and methods

Here are the essential details for all the drives we tested:

  Interface Flash controller NAND
Adata SE730H External SSD 512GB USB 3.1 Gen 2 Silicon Motion SM2258 Micron 3D TLC
Intel X25-M G2 160GB SATA 3Gbps Intel PC29AS21BA0 34-nm Intel MLC
Samsung Portable SSD T5 1TB USB 3.1 Gen 2 Samsung MGX 64-layer Samsung TLC
SanDisk Extreme Portable SSD 1TB USB 3.1 Gen 2 Marvell 88SS1074 64-layer SanDisk TLC

The SATA SSDs were connected to the motherboard’s Z270 chipset. The portable SSDs were connected via the motherboard’s USB 3.1 Gen 2 Type-C port.

We used the following system for testing:

Processor Intel Core i7-6700K
Motherboard Gigabyte Aorus Z270X-Gaming 5
Firmware F10B
Memory size 16 GB (2 DIMMs)
Memory type Corsair Vengeance LPX DDR4 at 2133 MT/s
Memory timings 15-17-17-35
System drive Corsair Force LS 240GB with S8FM07.9 firmware
Power supply Rosewill Fortress 550 W
Operating system Windows 10 x64 1803

Thanks to Gigabyte for providing the system’s motherboard, to Intel for the CPU, to Corsair for the memory and system drive, and to Rosewill for the PSU. And thanks to the drive makers for supplying the rest of the SSDs.

We used the following versions of our test applications:

  • IOMeter 1.1.0 x64
  • TR RoboBench 0.2a

Some further notes on our test methods:

  • To ensure consistent and repeatable results, the SSDs were secure-erased before every component of our test suite. For the IOMeter database, RoboBench write, and RoboBench copy tests, the drives were put in a simulated used state that better exposes long-term performance characteristics. Those tests are all scripted, ensuring an even playing field that gives the drives the same amount of time to recover from the initial used state.

  • We run virtually all our tests three times and report the median of the results. Our sustained IOMeter test is run a second time to verify the results of the first test and additional times only if necessary. The sustained test runs for 30 minutes continuously, so it already samples performance over a long period.

  • Steps have been taken to ensure the CPU’s power-saving features don’t taint any of our results. All of the CPU’s low-power states have been disabled, effectively pegging the frequency at 4.0 GHz. Transitioning between power states can affect the performance of storage benchmarks, especially when dealing with short burst transfers.

The test systems’ Windows desktop was set at 1920×1200 at 60 Hz. Most of the tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.



SanDisk’s Extreme Portable gave us every bit of portable performance we were looking for. It gobbled up our files without hesitation, at speeds often beating run-of-the-mill internal SSDs. We distill the overall performance rating using an older SATA SSD as a baseline. To compare each drive, we then take the geometric mean of a basket of results from our test suite.

The Extreme Portable turned in nearly as good a showing as the Samsung T5 did. That drive wowed us last year with its speed and polish. And though the novelty of portable SSDs with performance as good as their internal counterparts has faded somewhat in the months since, there’s no denying that SanDisk has put together an excellent product here. Plus, those months have done great things to the prices of these sorts of luxuries. In the graph below, the most compelling position is toward the upper left corner, where the price per gigabyte is low and performance is high.

SanDisk Extreme Portable

August 2018

The Extreme Portable’s price tag of $270 translates to 28 cents per gigabyte. That’s far more palatable than the 40 cents per gigabyte the T5 1 TB commanded with its suggested launch price of $400. Thankfully, that drive’s sticker has been slashed down to $270, too. 

If not for the exorbitant prices of DDR4, we’d be in a golden age of PC DIY-ism. Graphics cards are available again, CPUs have more cores than ever, and terabytes of solid-state goodness are available for shockingly little scratch. It’s great to see that the downward spiral of drive prices has extended to external SSDs, as well.

The SanDisk Extreme Portable ticks all of our boxes. It’s incredibly light and compact, it’s nicely adorned, and it performs as well as anything we’ve seen short of NVMe drives. Its reasonable asking price, encryption features, and IP55 certification are just icing on the cake. If you have frequent need of a durable external SSD to dump data into while on the go,  throw out your chintzy thumb drives and pony up for an Extreme Portable. It won’t do you wrong.

Comments closed
    • Dionysus
    • 4 years ago

    I care about my data. There isn’t much info about the chipsets, besides Marvell SATA-NAND controller, how about DRAM or the USB interface chip? Knowing this drive shares the same old Marvell controller as MX300, I know my data won’t be safe there. If it needs DRAM for 500GB and above, I know the power consumption will too high for a mobile environment. If such old controller needs no DRAM, endurance is going to be a problem for such new NANDs albeit exterior endurance looks nice. In a word, selling portable drives is a way of these manufacturers dumping binned NANDs and cleaning up inventory.

    • FireGryphon
    • 4 years ago

    I like the portable SDD reviews, especially as they come down in price and can be used more like big USB drives.

    • 4 years ago

    Another useful test would be to test it on USB2.
    Have no doubt it will say -backward compatible-and data wise it’ll be fine.
    But will it work at 2.5 watt ?? or does it need a dual-dongle??

    • demani
    • 4 years ago

    Not silly at all. I mean, I’m sure none of my usb sticks were rated IP anything, yet I’ve sent more than a few through the washer and drier and none have failed because of it (well, not directly attributable to that anyway). It’s one of the things about flash that would let me buy a drive even if it was only HD speed. Give me a slow portable but non-fragile drive and I will be quite happy.

    • derFunkenstein
    • 4 years ago

    it’s all good. she’s wearing a hat and a vest so it must be cold. 😆

    • tipoo
    • 4 years ago

    I just want to point out that carrying bag/purse laptop case at second 34 in the video

    Holy throttling batman!

    • DevilsCanyonSoul
    • 4 years ago

    Runs too hot compare to competing products. Returned it!

    • weaktoss
    • 4 years ago

    I didn’t mention it because it doesn’t come in the box, but they actually sent along a SanDisk-branded carabiner when they sent me the drive. So that seems to be exactly what the loop is intended for.

    • LocalCitizen
    • 4 years ago

    ah, thanks!

    • weaktoss
    • 4 years ago

    I’ll make a note of that for the future. If it helps, the bit of blue PCB you can see in the internal photo is actually an M.2 2280 stick, so you may be able to get a sense of the size from that.

    • godforsaken
    • 4 years ago

    May seem like a silly idea at first, but, given what it is advertised for, would it be worthwhile to drop it a few times, then run the testing suite again.. then rinse (literally) and repeat… see how long it lasts before it’s time to leave it under a rock in yellowstone

    • LocalCitizen
    • 4 years ago

    hard to tell the size from the photo. perhaps an m2 2280 stick can be placed next to it for scale?

    • Duct Tape Dude
    • 4 years ago

    Great transfer speeds for a Bluetooth speaker.

    • derFunkenstein
    • 4 years ago

    I’ll read the review in a moment, but I need to note that the way the enclosure has that gaping hole (for a carabiner presumably?) I thought it was a camera hole and that the enclosure was a phone case. And then I was wondering when TR started reviewing smartphone accessories. :p

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