We’ve seen well over 2GBps from Intel’s 750 series NVMe PCIe card drive, which plugs into a an open PCIe slot like a video card (an alternative to M.2 that desktop users should consider), so the SM951 NVMe may not be showing the full potential of NVMe. Intel told us it didn’t produce an M.2 version of the 750 because at top speed, the power draw exceeded what’s available from M.2 slots. Basically, not all the ducks are in a row yet to fairly evaluate AHCI versus NVMe. It is safe, however, to say that PCIe SSDs obliterate their SATA cousins in terms of raw sequential throughput. They also occupy a slot in your motherboard.
Here are the details on the drives involved in the testing.
Intel 530 360 GB
This is a decent drive for say an older NUC, or small-form-factor PC. But it’s still SATA and only a 500MBps/300MBps reader/writer at that. That’s certainly enough for the average user, and far faster than a hard drive, but not a product for enthusiasts. The biggest issue is that the 530 series appears still to be priced at about 80 cents per gigabyte—roughly twice what you’ll pay for the faster Samsung 850 EVO M.2.
Samsung XP941 PCIe AHCI
The XP941, with its Gen2 X4 PCIe interface, is a kick in the pants after a SATA SSD, but it pales in comparison to the performance of its newer siblings, the SM951 AHCI and NVMe. Still, if you find it at a bargain price, you won’t regret it. At least until Samsung’s new SM953 shows up and drives down the price of the SM951.
Samsung SM951 AHCI/NVMe
If you want the absolutely fastest M.2 PCIe drives on the market, these x4 PCIe SSDs are what you’re looking for. Lightning on a stick, your system will show a level of responsiveness you probably didn’t even realize was possible. The AHCI version is currently faster for large sequential transfers, while the NVMe version is great for server-type, queued loads. This may change as the NVMe implementation matures.
Kingston HyperX Predator PCIe
The Kingston HyperX Predator PCIe scored lower than the Samsung SM951 in artificial benchmarks, but did exceptionally well in our real-world copy tests. It also ships with an adapter card. Note: You'll see a steep retail price on the Kingston site, but steep discounts just about everywhere else.
Samsung 850 EVO M.2 SATA
This drive is faster than the Intel 530 and a whole lot cheaper, but performance drops with large data transfers. Not catastrophically, as with OCZ’s Trion 2.5-inch SATA drive, just down to about the 300MBps level. Still, it’s a very good SSD for SATA-only M.2 sockets.
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