Solid state drives are nearing the maximum data transference speed potential offered by the Serial ATA III interface, which tops out around 550 MB/s. Manufacturers wanting to meet the demands of speed-hungry users are looking beyond the 12-year-old interface. The successor may have already arrived with the Samsung 950 Pro M.2 solid state drives at the forefront. They reach new performance heights according to hardware reviewers and may be a sign of SATA III’s impending obsolescence.
What is M.2?
The M.2 specification provides speeds faster than SATA III in a smaller profile. It connects right into a motherboard slot—no cables for power or data transmission are required. Once referred to as the Next Generation Form Factor (NGFF) before it came to be standardized as M.2 in 2013 under the SATA revision 3.2 specification. The capabilities of M.2 extend beyond just data storage and could also be used for system expansion cards, including video, sound, and network.
Confusingly, M.2 cards come in several different sizes varying in both width and length.
Width
- 12 mm
- 16 mm
- 22 mm (most common)
- 30 mm
Length
- 30 mm
- 42 mm
- 60 mm
- 80 mm (most common)
- 110 mm
Most M.2 SSDs will put the width and length into a numeral designation.
Example:
- 2242 (22 mm × 42 mm)
- 2280 (22 mm × 80 mm)
- 2260 (22 mm × 60 mm)
When purchasing a M.2 card, consult your motherboards owner’s manual for M.2 compatibility information.
If you look at a M.2 card, you’ll notice notches on the connection end. Those notches indicate supported interfaces and act in a similar way to PCI and PCI-e connector notches, which prevent you from installing expansion cards into incorrect slots. There are several different keys or notch configurations under the M.2 standard and you must match the card to the slot. For M.2 SSDs, you’ll commonly see keys B and M.
A 2280 M.2 card.
What is NVMe?
M.2 is only half of the reason why SATA III may soon go extinct. NVMe, or NVM Express, is the other half. NVMe is a protocol that allows motherboards to use M.2 and PCIe SSDs as boot drives. Without it, you can’t boot from a PCIe or M.2 solid state drive. NVMe also allows PCIe and M.2 SSDs to reach optimal performance by providing faster speeds.
Benefits: Smaller Devices, Greater Speeds
The combination of M.2 and NMVe allows SSDs to move beyond the speed limits of SATA III while at the same time physically downsizing and eliminating the need for cables. Already compact SSD storage now allows for a further shrinking of notebooks and mini ITX systems.
Barriers to Adoption
Smaller, faster, and more efficient solid state drives sound good—but what’s the catch? Right now, there are several barriers to mass adoption of M.2 NVMe solid state drives. Let’s tackle each one.
A lack of competition, which is stagnating prices. The Samsung 950 Pro is currently the only drive out there that combines the small form factor of M.2 with the boot capability and speed of NVMe. Intel can produce—and likely will eventually—a M.2 NVMe drive, but they have not made any announcements yet. What they do have out already is their series of 750 NVMe PCIe SSDs, which are the size of your average expansion card.
With only two manufacturers backing M.2 NVMe however, prices aren’t moving anywhere fast. The Intel 750 starts at $390 for the 400 GB model while the Samsung 950 Pro starts at $200 for 256 GB. Mushkin announced the Hyperion M.2 NVMe SSD based on the Phison E7 controller back in January 2015, but that has yet to surface.
Heat will be a factor. While reviews have not stated the Samsung 950 Pro has a heat problem, that’s mainly due to the fact that it has a Dynamic Thermal Guard feature to protect it. NAND chips can heat up during heavy workloads, which can snowball into more problems for notebooks. One answer is to add heat sinks, but that may violate the 1.5 mm thickness (per side) allowance of the M.2 specification.
The performance jump from SATA to M.2 NVMe is not as great as the jump from platter to SSD. The performance benefits of moving from platter drives to SSD were enormous. Ars Technica’s benchmarks show a dramatic increase in read speeds (Up to three times faster than the 850 Pro drives) but write speeds vary. For IOPS write performance, the 950 Pro 512 GB raced far ahead of the 850 Pro 512 GB. But the 850 Pro 256 GB was on par (actually marginally faster) than the 950 Pro 256 GB.
SATA III SSD sizes are trending upwards. Samsung only makes the 950 Pro in two capacities: 256 GB ($200) and 512 GB ($350). In terms of cost per GB, they come in at $0.78 and $0.68 respectively. The 1 TB 850 Evo in comparison costs $360 and has a cost per GB of $0.36. Nowadays, buyers expect much more capacity for their money.
Is M.2 NVMe the true successor to SATA III for SSDs?
Do you recall the days when platter drive manufacturers were fighting back against SSDs by producing 10k RPM drives such as the WD VelociRaptor? For a brief period, it seemed hard drive technology would develop to a point where spinning discs could offer enough of a size and speed compromise to lure buyers from solid state disks.
Now, we know that those 10k RPM drives were nothing more than the last gasp for platter drives for performance systems. The question today is whether M.2 NVMe is the last gasp of SSDs as we know it or the future of data storage. Put another way, are they equivalent to the VelociRaptor drives or early SSDs?
Let us know your thoughts on M.2 NVMe SSDs in the comments below.
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