It is always good to stay on top of the latest technologies and be able to compare them to older technologies. Ultra M.2 is an form factor and interface for connecting drives system boards.
Ultra M.2 vs M.2
Ultra M.2 is generally faster than M.2.
- Ultra M.2 slots use PCIe 3.0 x4 ( or SATA )
- Regular m.2 slots use PCIe 3.0 x2 ( or SATA )
Some M.2 sockets only support SATA. Some support NVMe.
|Ultra M.2||PCIe Gen3 x4||x4 NVMe||socket 3 configuration|
|M.2||PCIe Gen3 x2||x2 NVMe||socket 2 configuration|
M.2 Socket Types
- M key - can use 2 to 4 lanes
- B key - can use up to 2 lanes
- B & M key - can fit both types of sockets
Two factors that affect drives using the PCIe bus:
- PCIe generation
- PCIe slots ( x2 vs x4 )
Using more slots will result in a faster drive.
Terminology: NVMe vs M.2 vs Sata 3
It is easy to get a lot of the terms mixed up especially whent they sometimes seem to be used ambiguously. This chart should be helpful:
|M.2||Drive Form Factor|
|2.4” SATA||Drive Form Factor - standard / normal sized SSD|
|mSATA||Drive Form Factor - smaller card shaped SDD|
|PCIe Add-In Card||Drive Form Factor - an actual card|
|SATA 3||Protocol / Connector|
|NVMe||Protocol / Connector|
|X4||number of PCIe lanes used|
SATA 3 the third revision of SATA or Serial AT Attachement. It is an interface for connecting storage media to a system’s host bus adapter (a card or builtin to the system board). NVMe or Non-Volatile Memory Express is an interface for connecting storage media through the PCIe Bus. This is generally much faster than SATA. M.2 is a drive form factor. You can actually have M.2 drives that use either NVMe connections or SATA connections. They both exist. You can actually even have USB based M.2 devices. M.2 used to be kmown as Next Generation Form Factor (NGFF).
PCIE gen3 x4 Ultra M.2
You might see these specified like this:
- “Gen 3.0 X4”
- “G3 x4”
Which drive did I choose?
I have a 1 TB n M.2 NVMe Drive as a primary OS drive in my Linux workstation. Besides booting my OS it also holds most of my development and testing VMs. It is pretty much the obvious choice and doesn’t really take a lot of shopping around. A regular SATA SSD would also be fine but this is just that much faster and not prohibitively expensive.
For my NAS I don’t use anything evel close to this. I have all old fashied, magnetic, spinning disks. This is totally fine for a NAS since I’m not really expecting it to be super responsive. The bottle neck is really the network.