Samsung SM951-NVMe (256GB) PCIe SSD Review
by Kristian Vättö on June 25, 2015 9:40 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. For full details of this test, please refer to this article.
In our The Destroyer trace, the SM951 NVMe is faster than the AHCI version despite having only half the NAND, but it still gets beaten by the SSD 750 (although the SSD 750 has more NAND as well). As I mentioned in the review, the SSD 750 has excellent small IO performance under intensive IO loads, resulting in much lower latency than what the SM951 offers, but since it performs more poorly with sequential IOs the average data rate is equivalent to the SM951 NVMe. What's surprising, though, is the fact that the SM951 AHCI that was pulled from the Lenovo laptop is in fact considerably faster than the stock SM951 we received straight from Samsung. I even ran the trace twice the ensure that it's not a benchmark anomaly, but maybe there is something wrong with my sample given that even the XP941 and several SATA 6Gbps drives outperform it.
The SM951 NVMe also has a higher share of high latency IOs than the SSD 750, but that's quite typical to smaller capacity Samsung drives.
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Dasa2 - Monday, June 29, 2015 - link
i would also like to know how cpu usage is affectedit may not be of any significance with a 4790k but with a i3\i5nuc?
i would also be interested to see if ram speed has any effect on such high speed ssd speed in a nuc since most people seem to buy 1600c11 sodimm for them
iwod - Thursday, June 25, 2015 - link
What is stopping us to getting a 32 Channel SSD Controller?Cost? Or we wait for 3D NAND to push to the max 3.2GB/s a PIC-E 3.0 x4 allows?
What's next then? PCI-E 4.0 isn't even on the Cannonlake Roadmap.
And even with the 4x PCI-E 4.0 it seems to be too little headroom for SSD.
Where is the next bottleneck?
Kristian Vättö - Friday, June 26, 2015 - link
There are some 32-channel controllers in the enterprise space, but as you suspected the reason why we don't see those in the client market is cost.Right now I would say the biggest bottleneck is software design because everything (except some enterprise applications) is still designed for high latency storage (i.e. load everything to RAM and as little disk access as possible, whereas by properly utilizing the low latency of SSDs applications performance could be improved.
stevae - Friday, June 26, 2015 - link
OK, so a couple of things here. first, while windows 10 10130 is still a little buggy, i already have 10147 and it is rock solid. many improvements. next, i am running it on a samsung 951. boots very nice, there is no more error when restarting like there was in 10130, and things are smooth. however, it doesn't run at full speed. on crystal disk mark i get 1569 sequential read, and 1474 sequential write. and my sm951 is the ahci version. but this leads me to the BIG quesiton, since you guys said that the hardware is the same between the ahci and nvme versions, does that mean when the nvme version comes out and is sold widely, that i can download firmware to turn my ahci version into a nvme version?yeeeeman - Friday, June 26, 2015 - link
These SSDs are good for driving the performance up, especially for datacenters. In home usage, I swear that a Samsung 840 PRO is gonna satisfy all your hidden performance dreams. Period.JKJK - Friday, June 26, 2015 - link
You really didn't get the low-queue-depth-performance-and-low-latency-for-client-workloads-part, did you?I'm going to get me a few of these, as soon as they're available.
Shinzon - Friday, June 26, 2015 - link
I just build new main desktop and added also a 951 AHCI version and the difference from my 840 pro to this is very noticeable, almost as from mechanic drive to a SSD all over again. I can even feel the difference from the 951 and to my 2 840 pros in raid 0. So that comment is not very professional :-)Shinzon - Friday, June 26, 2015 - link
@ Kristian VättöAs someone else already speculated, could we please research some more if the AHCI version can be re flashed to NVMe version ? Of course Samsung answer will be: not supported because it's OEM product, warranty void and the whole swada but I guess it's a question of getting a flash program that supports the controller EPROM they use and copy the NVMe firmware and then reflash the AHCI version. I think many would be interested in this.
Tack för dina altid fina reviews :-)
dcaxax - Friday, June 26, 2015 - link
Two words about Samsung SSD's. Never. Again.stevae - Friday, June 26, 2015 - link
yeah, why would you. they only lead the ssd world 95% of the time. sure, you go ahead and stick with that ocz crap.