The Samsung 950 Pro PCIe SSD Review (256GB and 512GB)
by Billy Tallis on October 22, 2015 10:55 AM ESTPerformance Consistency
Kicking things off, our performance consistency test saturates the drive with 4kB random writes for a full hour, with a queue depth of 32, the maximum supported by the AHCI protocol used by SATA and most PCIe drives. This puts the drive's controller under maximum stress and writes enough data to exhaust all free space and spare area on the drive. This is an unrealistic workload for any client use, but it provides a worst-case scenario for long-term heavy use, and it sheds light on how different SSD controllers behave and if their performance will hold up as they fill up.
The average of the last 400 seconds of the test gives us a steady-state IOPS rating that is usually very different from what the manufacturer specifies for a new, empty drive. We also quantify the consistency of the drive's random write performance, and provide plots of the performance over the course of the test.
Once steady state is reached, performance is determined more by the controller's algorithms than the interface speed, so it's not too surprising to see the 950 Pro performing similarly to other Samsung drives.
The consistency metric shows a surprising disparity between the two 950 Pros, with the 256GB performing much better.
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Comparing the graphs of the two 950s shows that the inconsistency of the 512GB drive comes from frequent jumps in performance above a solid baseline. This pattern holds even for the test with overprovisioning. Graphing the power consumption over time (not shown) reveals that the periods of lower performance have lower power. If the lower performance were due to periodic background garbage collection, then we would expect power consumption to be at least as high as when the drive is performing well. Instead, it appears that the 512GB drive is experiencing thermal throttling.
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With most of its time spent thermally limited, our 512GB sample's low average is explained. It appears that the thermal throttling mechanism is bumping the drive down to one of several discrete performance levels, rather than a continuous performance mechanism.
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Per Hansson - Wednesday, October 28, 2015 - link
If you really need it FXi there is always the announced Samsung SM953 drive.It's 110mm long due to the inclusion of the tantalum capacitors, otherwise it's very similar to the SM951...
http://www.samsung.com/semiconductor/global/file/i...
R3MF - Sunday, October 25, 2015 - link
i was under the impression that win7 (install disk) does not support nvme, so i'm curious as to how you went about getting Win7 on a 950?Kristian Vättö - Sunday, October 25, 2015 - link
There is a hotfix NVMe driver available for Windows 7: https://support.microsoft.com/en-us/kb/2990941blos - Monday, October 26, 2015 - link
I slipstreamed that hotfix (and almost 200 other fixes) using NTLite to a Win7SP1 image, wrote it back to usb, booted and it would still not allow me to install to a 951 NVMe drive... no drives found.Has anybody got this to work?
Windows 10 installs just fine but I have an unused W7 Pro license and I would really like to use it to active a W10 install.
I hear the next version of W10 will activate directly from W7 licenses... but hopefully that'll arrive in time before the W10 will really want the activation. Or perhaps re-arming to extend a bit?
Per Hansson - Wednesday, October 28, 2015 - link
Yes it works but you need to integrate it in boot.wim as well.I made some details here about it, also nothing an errors that MS is still to fix in that KB article.
Even though I reported it a long time ago:
http://www.overclock.net/t/1543242/found-samsung-s...
blos - Wednesday, October 28, 2015 - link
Ah that explains a lot, didn't know that the boot.wim was a different environment :)Quick search indicates that boot.wim integration is already available on the NTLite, so I guess it's playtime for this weekend :)
catavalon21 - Wednesday, October 28, 2015 - link
The test system doesn't have a discrete video card. Would a high-powered video card impact the performance of the M.2 PCIe setup?AnnonymousCoward - Wednesday, October 28, 2015 - link
No.Caramonn - Friday, October 30, 2015 - link
I've read the review and others and I guess I don't see a reason to get one of these drives yet. Am I missing something? It seems that the real world performance doesn't justify the nearly twice the cost as other Samsung SATA drives. I was really hoping that the rated speeds would translate into actual real world performance, but that doesn't appear to be the case.Tuishimi - Thursday, November 5, 2015 - link
$350... I could live with that. Sounds like a decent piece of hardware.