Samsung launched its new SM951 today, the first M.2 SSD with full support for both PCI-Express 3.0 and the M.2 standard. We’ve discussed M.2 previously — it’s the newest SSD interconnect and it ties storage directly to the PCI-Express bus via the NVMe standard rather than running the communication through the much slower SATA interface.
Currently, only a handful of motherboards offer M.2 slot and the ones that do are limited to just two lanes of PCIe 2.0 connectivity. The SM951, in contrast, is expected to hit a read speed of 2.15GB/s and write performance of up to 1.55GB/s. That’s far faster than PCI-Express 2.0’s typical 1.6GB/s read and 1.35GB/s write, and roughly 4x faster than the top performance you’ll see from a conventional SATA drive.
This slide, shown back in July, is actually outdated as far as performance is concerned, but accurately illustrates expected power consumption. Samsung claims it can drive 450MB/s of read performance and 250MB/s wite performance per watt of power consumption. That means full power will draw somewhere between 4-5W — too much power for mobile systems, certainly, but not much for desktops or servers.
Some of you may remember back to 2009, when Samsung released a marketing video to highlight the potential performance of its SSDs. Back then, the company built an enormous 24-drive RAID 0 that reached a peak sequential performance of just over 2GB/s. Five years later, Samsung’s single PCI-Express 3.0-based drive is hitting those types of numbers in just one card.
Whether or not PCI-Express 3.0 takes off as an M.2 interface standard is going to be an interesting question. There’s no reason that Intel and AMD couldn’t support it, but manufacturers would need to divert the relatively limited number of PCIe 3.0 lanes away from graphics hardware and over to the interconnect. Given that most gamers prioritize 3D performance over anything else, that’s going to be an intrinsically tough sell. Until Intel and AMD add additional lanes, even customers willing to shuck out for a 1TB drive wouldn’t see that kind of performance without a secondary controller card and a dedicated PCIe 3.0 slot.
For now, this is an industrial drive aimed at major enterprise and business applications, as well as fields like high frequency trading, but it’s not unreasonable to think we could see PCIe 3.0 versions of M.2 in the next few years, particularly since NAND flash is going to be the dominant form of high speed storage for the next 4-5 years.