The last few years have seen rapid advancements in flash technology including planar 1x nm NAND, TLC, and 3D V-NAND. External high-speed interfaces such as USB 3.x have also become ubiquitous. The advent of Type-C has also enabled device vendors to agree upon a standardized connector for their equipment (be it mobile devices or desktop PCs). These advances have led to the appearance of compact bus-powered direct attached storage units with very high performance for day-to-day data transfer applications.

Introduction and Usage Impressions

SanDisk launched the Extreme 900 SSD at Computex 2015. The claim to fame was the availability of almost 2TB of flash in a bus-powered enclosure with a USB 3.1 Gen 2 Type-C interface. It was one of the first 2TB-class external drives to arrive in the market. Though the Samsung Portable SSD T3 beat it to our review bench, we finally got SanDisk's review sample last month.

Compared to the Samsung Portable SSD T3 (a palm-sized unit), the Extreme 900 is much bigger - similar to that of a slim 2.5" external hard drive. The unit comes in at approximately 18 x 83 x 133 mm and weighs 210g. It has a Type-C interface, but, the package comes with both Type-C to Type-C and Type-C to Type-A cables. This ensures that the drive is compatible with a wide variety of systems currently in the market.

The Extreme 900 models put two of SanDisk's Ultra II SSDs in RAID-0 behind an ASMedia ASM1352R USB 3.1 Gen 2 to SATA 6Gbps RAID / port multiplier solution. The presence of the Ultra II SSDs is confirmed by CrystalDiskInfo.

SanDisk's Ultra II SSD has already been reviewed in detail before. The 1.92TB Extreme 900 uses two of the Ultra II 960GB SSDs. These SSDs use the Marvell 88SS9189 controller with SanDisk's 2nd Gen. 128Gbit 19nm TLC NAND. We will not go any deeper into the internal details of the Ultra II, but, one should note that it uses SanDisk's nCache 2.0 technology, where each die has a fixed number of blocks running in SLC mode. The 960GB Ultra II has 40GB of SLC cache, which translates to 80GB of SLC cache for the 1.92TB Extreme 900 as a whole.

In the rest of the review, we take a look at our testbed setup and evaluation methodology followed by our DAS benchmark numbers. In the final section, we take a look at the performance consistency and power consumption numbers.

Testbed Setup and Evaluation Methodology
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  • Holliday75 - Monday, April 11, 2016 - link

    Do those $10 enclosures support RAID 0? I'm sure there are some on the market, but to support RAID 0, USB 3.1 gen2? Doubt there are many if any on the market.
  • littlebitstrouds - Monday, April 11, 2016 - link

    I've got this 2 bay 3.1 gen2 from Startech. Have two 480gb Sandisk Ultra II SSD's running RAID 0. I get 420 MB/s read and write with my Macbook Retina. I'm on the road, so I haven't tried them on my desktop, with true 3.1 gen2 support yet.
  • ganeshts - Monday, April 11, 2016 - link

    Nice one.. it is not $10, but $95, but a good solution for sure.

    Unfortunately, it is not bus-powered or as compact as the Extreme 900. That said, it is definitely more flexible with the configurable RAID levels.
  • jameskatt - Saturday, May 7, 2016 - link

    I'd rather have a boring enclosure design that is as small and utilitarian as possible. No need for extra fins and doodads. Just do its job and stay out of the way.
  • digiguy - Monday, April 11, 2016 - link

    I wonder if we'll see at some point external enclosures capable of supporting PCIe SSDs that can saturate 10Gb/s and/or even use Thunderbolt 3 to transfer data up to 40Gb/s
  • name99 - Monday, April 11, 2016 - link

    "with a peak power consumption of around 8.1W. SanDisk suggests using USB ports capable of delivering up to 10W of power for optimal performance. It is obvious that using a port capable of delivering only the usual 5W will heavily hamper the performance of the unit.

    I'm sorry but this is an unacceptable ending to a pretty good review.
    There is no such thing as a "usual 5W USB port". A USB2 port will give you 2.5W, a USB3 port will give you 4.5W. Hoping that you'll be lucky and get more is a recipe for tears.

    Next, since SANDisk provide an A-connector, what actually HAPPENS when you use a 2.5 or 4.5W port? I'm somewhat dubious of the claim that it will just "heavily hamper the performance". At the very least I'd like to see some testing of this, with verification that the device does not simply randomly disconnect when it wants to power-draw beyond the allowed limit. Even assuming it is well-enough engineered to run properly on these lower power-draws, how much of a performance hit are we talking?

    This is part of a larger problem that, especially in the context of external drives (and, to some extent, WiFi equipment) AnandTech lives in blissful ignorance of the real world. Sure your labs don't contain a single devices manufactured before January 2016, but in the real world, a substantial use case for external USB drives involves their being swapped between different machines. THIS is why it REALLY matters to know how well they can handle being connected to older ports.

    This is not just some weird corner case, like a person complaining "well you didn't test that new SATA SSD drive when you connect it to 2007 SATA-66 box, and I really care about that situation"; it gets to the actual fitness of purpose for I would guess many, if not a majority, of the use cases of this sort of external USB drive.
  • ganeshts - Monday, April 11, 2016 - link

    No disconnects. Checked with a traditional USB 3.0 port. Some sort of throttling going on, which reduces the speed.
  • DanNeely - Tuesday, April 12, 2016 - link

    All hyperbole from name99 aside; some degree of benchmarking at lower power levels needs to be done for all high power usb flash devices for the next few years. Not necessarily the full suite; but one or two tests suitable to characterize what the fallback performance levels will be for people not having the latest and greatest hardware to plug them into.
  • epobirs - Monday, April 11, 2016 - link

    Which is why the SIIG USB 3.1 Gen 2 single bay enclosure comes with a dual host port cable, Type A on both ends.

    I have a 480 GB Patriot Blast SSD in it and it does a pretty nice job of saturating the SATA bus. Things should get more interesting if and when somebody produces an SSD controller that avoids the SATA bottleneck and taps into USB 3.1 fully.
  • TheUsual - Monday, April 11, 2016 - link

    No 'The'? I don't think every device deserves a 'The' at the beginning of the review, just the very important, well known devices.

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