So right off the bat I'll say that I'm a Software Engineer and I've been building computers for decades (up until 5-6 years ago) so I am technology literate, however trying to understand these new storage technologies is driving me up a wall. I think the major issue is that every article I read explains one thing and then turns right around and contradicts itself in the very next sentence. For example:
"M.2 is the SSD form factor whereas NVMe is a data transfer protocol."
(very next line)
"NVMe drives use the M.2 form factor."
(very next line)
"Make sure your M.2 drive is utilizing the NVMe interface protocol."
So what the hell is NVMe, a protocol or a physical type of drive? A protocol or an interface to plug the drive into?
Then you go on YouTube and see NVMe vs SSD vs M.2 vs HDD. Well if M.2 is just an SSD form factor, and NVMe is just a transfer protocol, then what the hell are they comparing? Should they be saying M.2 SSD using SATA vs M.2 SSD using NVMe vs 2.5 inch SSD using SATA vs HDD?
Then I go online and see an article "Which is faster NVMe or PCIe?" Well if NVMe is the fastest [protocol] then why are they comparing it to an interface?
You see where I'm going with this. I know for a fact that these terms are not interchangeable, so I have no idea why no one seems to be capable of explaining this clearly. I could if I could understand it first. I haven't even gotten into the 2×4 4×4 Gen 3/4 crap yet.
I just want to find an AM4 motherboard that supports two of the fastest storage devices out there on the board. Most of the boards I've seen only have x1 Gen 4 and x1 gen 3. Which makes no sense, but whatever. I can't even figure out which slots to look for and what drives to stick in there. Last time I built a computer there were two options… SATA HDD or SATA SSD. SATA SSD was cutting edge.
If anyone out there understands this stuff (extremely well) could you please help me make sense of it.
Best Answer
TLDR: NVMe is faster. NVMe is PCIe used for storage.PCIe is always faster than SATA
I think the easiest way to understand this is to break it up into electrical/data standards and physical form factors.
Your 'traditional' 2.5 and 3.5 inch hard disk drives use physical and electrical sata standards for connectors
M.2 is a different family of connectors physically
By Sayeen - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=130292724
You'd notice the top and bottom pairs of connectors are keyed differently.
The top two are SATA M.2 and the bottom 2 are PCIe M.2
NVMe is the storage protocol that PCIe M.2 drives use - so all M.2 NVMe drives are PCIe. There's a few 'full sized' PCIe SSD around as well, but that's generally outside the scope of most folks who arn't running a rack at home for fun
Generally as of 2023, most M.2 drives are 2280. There's exceptions but you don't need to worry about them (the last 2 numbers indicate length in mm). Most PCs unless the manual says otherwise will accept either.
Its backward compatible. Gen 4 is faster than Gen 3 - its exactly the same as with different 'full sized' PCIe generations. I think Gen 5 uses a different physical connector. Basically the bigger number the better.
Practically if you want the fastest drive, match the generation of your slot with the drive (so if you have a PCIe gen 4, get a gen 4 compatible SSD, and if you have gen 3, get a gen 3 or 4 drive), and compare the ratings of the options you have - since implementations, things like controllers and actual chips differ.
Most desktop PCs will support Sata or NVMe/PCIe drives UNLESS stated explicitly otherwise