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Samsung SM951 NVMe M.2 PCIe 256GB SSD Review

By: Jon Coulter | PCIe in Storage | Posted: Jun 10, 2015 2:09 pm
TweakTown Rating: 96%Manufacturer: Samsung

Final Thoughts




Samsung continues to impress us. In our opinion, they currently have the fastest consumer SSD's on the market. The main drawback of the SM951 series is availability. Where can you buy one? In addition, will it run as expected on your machine? Remember, the SM951 is only qualified for OEM motherboards.



We applaud Samsung for embracing the M.2 form factor. We are simply amazed that Samsung can deliver in such a tiny package what we feel is the best performing consumer SSD we've ever tested. We did not think we would see a consumer drive that can outperform the 750 series so soon. The SM951 NVMe set lab records left and right. While it is true that in a heavy workload scenario the 750 Series has an edge, it's also true that the majority of consumers will never run heavy workloads.


When comparing the SM951 AHCI to the NVMe version, it's important to focus on random performance rather than sequential performance. Sequentially, both versions perform similarly, but sequential performance is not nearly as important as random performance. Our PCmark 8 testing highlights the impact random performance has when running applications. The NVMe drive even though it is a smaller capacity with a lower sequential write speed is able to deliver 18% better overall performance due to its NVMe protocol. Throughout our testing, the SM951 NVMe drive was able to significantly outperform the AHCI version due to a higher Queue Depth in the NVMe protocol. Samsung puts a visual perspective on what NVMe brings to the table with the following chart:




When comparing the SM951 NVMe to the Intel 750 Series drives, we would point out that the SM951 has much better small file performance, as illustrated by our ATTO sequential read chart. Small file transactions comprise the vast majority of transfers in a consumer OS environment and the SM951 is able to outperform the 750 series by as much as 5X up to 16KB transfers. Because of this, we feel that the SM951 NVMe SSD will provide better performance than the 750 Series for the majority of consumers.


Because we perform most of our evaluations with the test subject running as our boot volume, we can comment on how the drive performed with our OS. Until now, we've been of the opinion that most SSD's will provide a similar user experience, but the SM951 NVMe is different. We were able to notice a big difference in how fast our system booted. But, what really grabbed my attention is how much faster Windows loads with an SM951 NVMe drive. There has always been a wait time (think spinning circle next to your curser) at the desktop for Windows to fully load, but not with this SSD, there is literally no perceivable wait time; that spinning circle next to your curser, it's gone! Installing Windows updates is literally twice as fast as any other drive or array I've ever used. Programs launch so fast it's hard to believe your eyes. This is the reason we test boot volumes. We can tell you about what matters most; user experience.


The SM951 will probably never make it to the masses, it was never intended to. This is just speculation on our part, but we believe Samsung is about to launch a similar drive with even better performance in the near future that will be available through normal retail channels. The SM951 is just a taste of what's on the horizon.


The M.2 form factor is driving innovation and we find it the most appealing of all form factors. There is something to be said for a drive that just disappears into your motherboard and doesn't take up a PCIe slot.




  • Fastest consumer SSD
  • Most appealing form factor
  • Low power requirement




  • Availability

Product Summary Breakdown

TweakTown award
Quality including Design and Build98%
General Features96%
Bundle and PackagingN/A
Value for Money89%
Overall TweakTown Rating96%

The Bottom Line: Samsung's SM951 NVMe SSD is the fastest OS Disk we've ever used and it packs all that performance into the most appealing form factor.

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