Samsung SM951 (512GB) PCIe SSD Review
by Kristian Vättö on February 24, 2015 8:00 AM ESTAnandTech Storage Bench - The Destroyer
The Destroyer has been an essential part of our SSD test suite for nearly two years now. It was crafted to provide a benchmark for very IO intensive workloads, which is where you most often notice the difference between drives. It's not necessarily the most relevant test to an average user, but for anyone with a heavier IO workload The Destroyer should do a good job at characterizing performance.
AnandTech Storage Bench - The Destroyer | ||||||||||||
Workload | Description | Applications Used | ||||||||||
Photo Sync/Editing | Import images, edit, export | Adobe Photoshop CS6, Adobe Lightroom 4, Dropbox | ||||||||||
Gaming | Download/install games, play games | Steam, Deus Ex, Skyrim, Starcraft 2, BioShock Infinite | ||||||||||
Virtualization | Run/manage VM, use general apps inside VM | VirtualBox | ||||||||||
General Productivity | Browse the web, manage local email, copy files, encrypt/decrypt files, backup system, download content, virus/malware scan | Chrome, IE10, Outlook, Windows 8, AxCrypt, uTorrent, AdAware | ||||||||||
Video Playback | Copy and watch movies | Windows 8 | ||||||||||
Application Development | Compile projects, check out code, download code samples | Visual Studio 2012 |
The table above describes the workloads of The Destroyer in a bit more detail. Most of the workloads are run independently in the trace, but obviously there are various operations (such as backups) in the background.
AnandTech Storage Bench - The Destroyer - Specs | ||||||||||||
Reads | 38.83 million | |||||||||||
Writes | 10.98 million | |||||||||||
Total IO Operations | 49.8 million | |||||||||||
Total GB Read | 1583.02 GB | |||||||||||
Total GB Written | 875.62 GB | |||||||||||
Average Queue Depth | ~5.5 | |||||||||||
Focus | Worst case multitasking, IO consistency |
The name Destroyer comes from the sheer fact that the trace contains nearly 50 million IO operations. That's enough IO operations to effectively put the drive into steady-state and give an idea of the performance in worst case multitasking scenarios. About 67% of the IOs are sequential in nature with the rest ranging from pseudo-random to fully random.
AnandTech Storage Bench - The Destroyer - IO Breakdown | |||||||||||
IO Size | <4KB | 4KB | 8KB | 16KB | 32KB | 64KB | 128KB | ||||
% of Total | 6.0% | 26.2% | 3.1% | 2.4% | 1.7% | 38.4% | 18.0% |
I've included a breakdown of the IOs in the table above, which accounts for 95.8% of total IOs in the trace. The leftover IO sizes are relatively rare in between sizes that don't have a significant (>1%) share on their own. Over a half of the transfers are large IOs with one fourth being 4KB in size.
AnandTech Storage Bench - The Destroyer - QD Breakdown | ||||||||||||
Queue Depth | 1 | 2 | 3 | 4-5 | 6-10 | 11-20 | 21-32 | >32 | ||||
% of Total | 50.0% | 21.9% | 4.1% | 5.7% | 8.8% | 6.0% | 2.1% | 1.4 |
Despite the average queue depth of 5.5, a half of the IOs happen at queue depth of one and scenarios where the queue depths is higher than 10 are rather infrequent.
The two key metrics I'm reporting haven't changed and I'll continue to report both data rate and latency because the two have slightly different focuses. Data rate measures the speed of the data transfer, so it emphasizes large IOs that simply account for a much larger share when looking at the total amount of data. Latency, on the other hand, ignores the IO size, so all IOs are given the same weight in the calculation. Both metrics are useful, although in terms of system responsiveness I think the latency is more critical. As a result, I'm also reporting two new stats that provide us a very good insight to high latency IOs by reporting the share of >10ms and >100ms IOs as a percentage of the total.
The SM951 takes the lead easily and provides ~34% increase in data rate over the XP941. The advantage over some of the slower SATA 6Gbps drives is nearly threefold, which speaks for the performance benefit that PCIe and especially PCIe 3.0 provide.
The latency benefit isn't as significant, which suggests that the SM951 provides substantial boost in large IO performance, but the performance at small IO sizes isn't dramatically better.
Despite the lowest average latency, the SM951 actually has the most >10ms IO with nearly 2% of the IOs having higher latency than 10ms. I did some thermal throttling testing (see the dedicated page for full results) and the SM951 seems to throttle fairly aggressively, so my hypothesis is that the high number is due to throttling, which limits the drive's throughput momentarily (and hence increases the latency) to cool down the drive.
However, the SM951 has the least >100ms IOs, which means that despite the possible throttling the maximum service times stay between 10ms and 100ms.
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Kristian Vättö - Tuesday, February 24, 2015 - link
PCIe adapters are fine for review purposes and are in fact more easily serviceable than M.2 slots tend to be.Samus - Tuesday, February 24, 2015 - link
Thank you for pointing out all capacities are M2 2280 DOUBLE SIDED. That is missing from virtually all reviews, sales material and eCommerce sites for M2 drives. Newegg has been pretty good about taking pictures of both sides of many drives, though.This is important to me because I work with HP Elitebook's and the newest generation of the Elitebook 810 (G2) and 820\1040 all require single-sided. The 840 has room for M2 DS modules, though.
Flash13 - Tuesday, February 24, 2015 - link
The company is not trustworthy! Buy at your own risk. Good Luck.youtard - Tuesday, February 24, 2015 - link
hurr!Wardrop - Tuesday, February 24, 2015 - link
Does this form factor work in standard desktop PCI-e 4x slots?DanNeely - Tuesday, February 24, 2015 - link
It's an m-2 plug, you need an adapter to fit it in a standard pcie slot.wtallis - Wednesday, February 25, 2015 - link
When discussing NVMe, please make it clear that the chipset and motherboard firmware only matter for booting off the drive; they don't need any updates to allow a compatible operating system to access the drive as something other than the boot volume.(As for what the motherboard firmware needs to gain in order to allow booting from NVMe devices, it's just a loadable UEFI device driver. Even if your motherboard doesn't have such a driver built-in, you could load it from some other storage device and then boot off the NVMe drive.)
ericgl21 - Wednesday, February 25, 2015 - link
I wonder if Samsung (or any other OEM) would be willing to sell a 1TB m.2 NVMe PCIe3.0 x4 SSD with SLC NAND with a 2280 form factor?Many professionals would appreciate the speed and reliability that SLC NAND provides.
Sure, it would cost a lot, but so do the Samsung SM951 and Intel P3700.
If that's not possible with current 16nm manufacturing, then a 512GB would also be nice. :-)
Just my 2 cents.
baii9 - Wednesday, February 25, 2015 - link
reliable on nand? Reliable controller matters, high endurance nand matters, I think nand are "reliable' enough already(compare to that lovely controller).IlikeSSD - Wednesday, February 25, 2015 - link
looks like Samsung paid for not showing OCZ in consistency and mixed workload tests )))))