The Samsung 950 Pro PCIe SSD Review (256GB and 512GB)
by Billy Tallis on October 22, 2015 10:55 AM ESTRandom Write Performance
The random write test is confined to a 16GB portion of the drive, which is otherwise empty. This allows the drive to demonstrate much higher performance than on our performance consistency test that fills the drive. Tasks like installing software updates can modify a lot of files, but aren't hitting the entire disk. Random writes to the entire disk are usually found only in enterprise workloads such as large databases.
The 950 Pro's random write speeds aren't benefiting at all from the PCIe interface or the NVMe protocol, and are about 20% slower than the SM951. Since it's happening to both drives it probably isn't a thermal issue, so this may be the result of a firmware change. Still, the Intel SSD 750 is the only retail drive that significantly outperforms the tightly clustered competition.
The higher power consumption during the random write test is a problem, since it's not buying any extra performance.
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After increasing significantly from QD1 to QD2, performance and power drop slightly and stay flat for most of the rest of the test. At the very end, a slight drop in power for the 512GB and a more significant drop for the 256GB may indicate a change in what background processing is going on; the drive may be postponing some garbage collection during the onslaught of writes at the maximum queue depth, or it may be a coincidental case of the background processing catching up and throttling back near the end of the test.
Random Read Performance
Our random read performance test is conducted on a full drive and tests queue depths from 1 to 32. We focus primarily on the lower queue depths that are typical of interactive use, but also look at how the performance and power scales to more intensive loads. For desktop use, searching and virus scanning are typically the biggest sources of random reads, and they can exercise some of the larger queue depths.
The strong random read performance of the 950 Pro provides great justification for its status as the a flagship drive for the consumer market.
The 950 Pro's power consumption is moderately higher but nowhere close to being proprotional to the performance advantage; the 950 Pro doesn't have to run hot to offer great performance.
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Power and performance scaling look very typical here, except I had to expand the performance axis for the 950 Pro. Both drives pass SATA's limits at or before QD16.
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Billy Tallis - Thursday, October 22, 2015 - link
If I'd had more time, I probably would have done more informal testing on some older machines. I can at least assure you that the drive doesn't seem to have any trouble in a PCIe 2.0 x2 M.2 slot on my personal Haswell machine. Next time I'm poking around in my Lynnfield server I'll be checking how the pcie drives work, especially power management. But I probably won't do a full suite of performance tests, just enough to get a rough idea for how fast drives perform on a slower link. And I really don't have a clue when I'll get around to this, because I've still got quite the backlog of drives to review.hansmuff - Thursday, October 22, 2015 - link
Understandable, thanks for the PCIe 2.0 update.The_Assimilator - Thursday, October 22, 2015 - link
Thermal throttling is disappointing but shows that M.2, like SATA Express, is DOA. PCIe drives with heatsinks, or preferably U.2, is the future - hopefully with the Z200 series chipsets, manufacturers will ditch SATAe in favour of U.2 and we can finally get a worthy successor to SATA3.MrSpadge - Thursday, October 22, 2015 - link
DOA it certainly is not. You're free to attach a tiny RAM heatsink on the drive and be fine. Or simply forget about throtteling in real world usage (unless you use it in a server).Redstorm - Thursday, October 22, 2015 - link
Under a normal client workload you don't get anywhere near triggering the thermal protection so adding heat sinks is not required. Agree SATA Express was still born. M.2 is far from it, if you look at any new release ultrabook you will find a M.2 SSD under the lid.The_Assimilator - Friday, October 23, 2015 - link
M.2 is a great solution for replacing 2.5" SSDs in space-limited applications like ultrabooks, but for *absolute maximum performance without thermal throttling*, 2.5" U.2 drives a la Intel's 750 are still the way to go.zodiacfml - Sunday, October 25, 2015 - link
It depends on the designer on how much throttling they would allow or not. U.2 allows more freedom though but I reckon would be much more expensive and less dense in the future.user_5447 - Thursday, October 22, 2015 - link
Why everyone keep saying that BIOS/UEFI must support NVMe to boot into OS?You can install GRUB bootloader on cheap small USB flash drive and use it to boot from NVMe drives on any system, since GRUB itself supports NVMe for few years now.
And yes, GRUB supports booting into Windows 8.1 / 10.
bji - Thursday, October 22, 2015 - link
They say it because it's true. Nobody wants to have to manage a USB drive just for booting their system. You can also install a floppy drive and boot from that, would you recommend that also? How about keeping a separate computer up constantly to support PXE booting from the network? Would you recommend that level of headache to someone who just wants to boot their frickin computer?bji - Thursday, October 22, 2015 - link
By the way, of all of the things I have to deal with when installing/upgrading Linux systems, grub is the most painful and problematic, by MANY orders of magnitude. I would *NEVER* recommend that a non-technical user have anything to do with grub, especially not for something as silly as booting a PC into Windows off of an NVMe drive.