Samsung SM951 (512GB) PCIe SSD Review
by Kristian Vättö on February 24, 2015 8:00 AM ESTFinal Words
When the news that the SM951 isn't NVMe enabled hit the Internet, there was a lot of disappointment around. Understandably many were expecting that the SM951 would merely be an evolutionary step from the XP941 because AHCI command set would still limit the full potential of the PCIe interface, but Samsung proved us all wrong. The SM951 is far from being a marginal step up from the XP941 because in most of our tests the SM951 beats the XP941 by a 50-100% margin. As a matter of fact, the upgrade from XP941 to SM951 is bigger than going from a SATA 6Gbps SSD to the XP941. Despite the lack of NVMe, there's no arguing about the fact that the SM951 is the fastest client SSD and by a very healthy margin.
From a performance perspective I have absolutely no complaints aside from thermal throttling. I wouldn't consider it to be a major issue because regardless of some throttling in synthetic tests, the SM951 is easily the highest performing drive. The Destroyer test takes about 10 hours to run on modern drives, so if throttling was a real issue it would show up more clearly in the results too. Besides, my half-open testbed isn't ideal for airflow either, but since I haven't encountered noticeable throttling in the past I wanted to mention it in case anyone runs into performance issues with the drive.
Right now the biggest issue with the drive is its nearly nonexistent availability, though. If you want to get your hands on the drive today, the only known way to do that is to buy Lenovo's ThinkPad X1 Carbon that is configured with a PCIe SSD. The cheapest configuration with a 512GB SM951 comes in at $1,709.10, so there's practically no sane way to get access to the drive (unless, of course, you want the X1 Carbon laptop as well and are willing to pay the price).
That brings us to the next subject. Since retail availability isn't expected until late May at the earliest, there's a chance that the SM951 will no longer be the fastest SSD once it's actually available for purchase. At CES last month, several SSD vendors told me that they should have PCIe SSDs ready for Computex, which is in early June, i.e. right after the SM951 is scheduled to start shipping.
If the SM951 was available today, I would have no reason not to give it our "Recommended by AnandTech" award. Being hands down the fastest client SSD on the market is enough justification for the award, but because the drive won't be shipping for several months I can't be sure that I'm still recommending the SM951 once it's available. For now the only thing we can do is wait, but at least we can do it in peace by knowing that the future is quick and bright.
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Makaveli - Tuesday, February 24, 2015 - link
I would love to see two Samsung 850Pro 256GB drives in Raid 0 vs this.BPB - Wednesday, February 25, 2015 - link
I was really hoping to see this compared to a RAID 0 setup. I'm considering getting one of these or a competitor's version in 2 or 3 months, but I'm also considering just getting another Samsung SSD and creating a RAID 0 setup.Flash13 - Tuesday, February 24, 2015 - link
Why trust Samsung? I don't anymore.youtard - Tuesday, February 24, 2015 - link
hurr!icrf - Tuesday, February 24, 2015 - link
Suggestion for the graphs/charts picked from a drop down: make them all have the same scale, so when flipping between them, it's easier to compare from a visual shift. Ideally, it wouldn't be a drop down, but a set of checkboxes that would show/hide each line graph on the same chart to see more than one at once. If you're pre-rendering the charts, I understand how that would be a problem.Edgar_in_Indy - Tuesday, February 24, 2015 - link
It would be a lot easier to get excited about this drive if there were real-world numbers to look at. I find it frustrating that most hard drive reviews don't show some basic load times. You know, how long to boot windows, to load a level in a game, copy a huge file, etc.It would make it much easier to judge the relative performance of drives, and decide whether the results justify the upgrade cost.
willis936 - Wednesday, February 25, 2015 - link
While it requires more technical knowledge from the reader it actually gives a lot more useful info. Time to load windows? Is that on first boot after install? After updates? After 100 programs are installed? After 10 r/w cycles? After the drive isfiles filled? With overprovisioning? I'd personally much rather synthetic tests that cover most cases so you can extrapolate subjective performance from it. You just have to know which workloads line up with which tests.DanNeely - Wednesday, February 25, 2015 - link
Page 2 of the article, section "A Word About Storage Benches and Real World Tests".TLDR version: "Too much background IO for consistent results to be possible."
Edgar_in_Indy - Wednesday, February 25, 2015 - link
From that same section: "I know some of you have criticized our benchmarks due to the lack of real world application tests, but the unfortunate truth is that it's close to impossible to build a reliable test suite that can be executed in real time. Especially if you want to test something else than just boot and application launch times, there is simply too many tasks in the background that cannot be properly controlled to guarantee valid results. "Okay, then. So a complicated real-world test is difficult to duplicate. But why can't we at least have the simple "boot and application launch times" he referenced? And what about a large file copy, like I already mentioned? That's something most people could easily relate to. And time to compress a large group of files? Etc.
If the whole idea of an SSD is to do things faster, then it would be helpful to get a stopwatch involved in these types of review, at least a little bit!
Or if it really is "Mission Impossible" to document any real world speed improvements, then I can't help but wonder if this is kind of like people paying premiums for high-performance memory, with very little real-world return.
zodiacfml - Wednesday, February 25, 2015 - link
Why not do a benchmark of a Windows installation in a virtual machine from a RAM disk?