Final Thoughts
Samsung enjoys a large lead in both controller and flash technology over its competitors. 3D V-NAND stacked 32 layers-high covers the flash. Only Samsung has this. And the UBX isn't Samsung's first PCIe-to-flash controller efficient enough for power-restricted M.2 applications; it's a second-generation part.
Marvell is trying to catch up, but even the second-gen Altaplus controller trails Samsung's effort. SandForce, now part of Seagate, could make some noise at Computex. However, the SF3700 is two years late and we haven't seen anywhere near 2150 MB/s in our behind-the-scenes testing. Phison, JMicron and others plan to release PCIe-based controllers in 2015. We're not holding our breath for Samsung-class performance right out of the gate, though.
Our story today focused on the M.2 form factor, so Intel's SSD 750 wasn't represented. In a few days, an SSD 750 400GB will arrive. Right behind that we should be receiving a trio of SM951-NVMe drives. Once all of the pieces are in place, we'll publish a comparison of high-end NVMe products.
I hate to say that the products in this piece are in a lower-tier, but the SM951-NVMe is going to be more expensive. And we don't expect a large performance increase over the AHCI-based SM951 in client workloads, so the models we tested should provide better value to enthusiasts. Without samples in the lab, we can't say for sure. At some point, however, excess becomes superfluous. Time will tell.
The 128 and 256GB SM951s raise some questions about the 512GB model's performance. The Lenovo-specific drive is certainly fast, though there are areas we'd expect it to be quicker if there were no restrictions on its speed. The difference in sequential reads between all three models at a queue depth of four is 500 MB/s, or basically a SATA 6Gb/s SSD.
Samsung's 128GB SM951 is a great value for non-gamers. Games take up a lot of space, and some of us don't get to play as often as we'd like. Others just want a notebook capable of blazing-fast performance. Business users can certainly appreciate the extra battery life, and excellent 4KB read performance makes quick work of large email databases.
The 256GB model gives you room to store a few of your favorite games and professional applications. It delivers 90% of the performance at nearly half the cost of the 512GB drive. That wouldn't mean much in the congested SATA space. But this is PCIe-attached. It's the future, where you'll find the real performance story. Consider 256GB today's sweet spot.
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Chris Ramseyer is a Contributing Editor for Tom's Hardware, covering Storage. Follow him on Twitter and on Facebook.
