M.2 & PCIe SSDs - format is not everything
After the sata600 port lost its usefulness, a new standard was needed to increase the transfer speeds further. Instead of reinventing the wheel, the SSD industry decided to use the existing PCI-express standard. Almost all top models therefore make use of this fast plug, often in combination with the NVMe protocol optimised for this purpose
M.2, and yet SATA?
There are roughly two choices an SSD manufacturer can make for this scenario. Most PCIe SSDs today use the m.2 form factor. M.2-SSDs can be installed directly in a slot on the motherboard, but also in many modern laptops. The other option is a separate PCIe expansion card. This offers advantages in terms of compatibility with older platforms and cooling possibilities, but the more compact m.2 format seems to win the battle.
However, the m.2 format does not say anything about the speed of an SSD. It is perfectly possible to transmit a regular SATA signal via the m.2 connector. For example, we have also tested the m.2 versions of the Crucial MX500 and Samsung 850 Evo, which are identical in performance to the normal 2.5" models
NVMe for everyone!
If you want a really fast SSD, you are looking for the combination of the PCIe port with the NVMe protocol. This market has been turned on its head in recent months, for example by the introduction of the Toshiba OCZ RCZ RC100. In terms of performance, this drive can best be described as a SATA SSD with the limits of the SATA interface removed - it performs well in real-world tests, but is absolutely not able to withstand heavy loads or use with little free space. However, it is very competitively priced for a NVMe SSD.
Really fast SSDs
Until recently, really fast NVMe SSDs were almost exclusively produced by Samsung, but with the 2018 edition of its Black SSD, WD can compete fairly with the Samsung 970 Evo. In some tests, it is even faster, although Samsung's youngest on average remains just that little bit quicker. On the other hand, the WD is more energy efficient. In terms of price, the manufacturers seem to pay close attention to each other, so one week the WD is a bit cheaper and the next week the Samsung, but the overall impression is good with both drives.
A glimpse of the future
If you want the highest performance per se, then the Samsung 970 Pro is for the time being the fastest regular SSD you can buy. However, it is considerably more expensive than the 970 Evo and only relatively faster. In terms of performance of a totally different level, you be looking at the Intel Optane SSDs, and specifically the 900p and its server brother the DC P4800X. These SSDs do not use traditional flash memory, but the new 3D XP point memory that Intel has developed in collaboration with Micron.
The big advantage is that this type of memory is not only fast with many reading and writing tasks being processed simultaneously, but also with low queue depths, which is a more realistic scenario for daily use. At the moment, however, the Optane SSDs are still very expensive: for the 480GB version tested by us, you pay at least 600 dollars.