Solved 2 M.2 slots which slot is faster?

I have an asus Z390M-PRO GAMING (wifi) motherboard that has 2 M.2 slots, I looked in the manual but I couldn't tell the difference (I'm still learning the new technology) I'm asking because I have a Samsung 970 evo plus that's 250 gb and that is pretty quick but I also have an Intel M.2 that is 500gb. So I was thinking about using the Intel M.2 for my OS and use the Samsung with the Intel Rapid Storage software as cache for the Intel m.2 or at least use the Samsung m.2 for the page file,temp files, web browser cache etc.


The website for my motherboard below:

I've had an ASUS Motherboard with 2 M.2 slots. They label them M.2 -1 and M.2 - 2 (don't have that computer or the documentation here now).

I seem to remember the following restrictions: M.2-1 was slightly faster (but you will not notice any difference).
Only M.2-1 could handle both SATA and PCI.E M.2 sticks.
M.2-2 could only handle PCI.E interface AND it did not work if you put in a second graphics card. This was un-documented and it took a while before i figured it out.

It is all in the instruction manual for that motherboard. If you can't find it but you want to be sure, you need to contact Asus.
Tom's hardware is a better place to ask about this, since this forum is about Windows and not Hardware.

From your user manual they look to be the same:

M.2_1 supports PCIe or SATA
and M.2_1 shares SATA 2 when using a "SATA" device.

M.2_2 supports only PCIe






The Samsung 970 EVO Plus is an M.2 PCIe 3.0 x 4

I can't tell what the Intel is without a model number.

Ghot said:

M.2_1 supports PCIe or SATA
and M.2_1 shares SATA 2 when using a "SATA" device.

M.2_2 supports only PCIe



View attachment 43220


The Samsung 970 EVO Plus is an M.2 PCIe 3.0 x 4

I can't tell what the Intel is without a model number.

Click to expand...

Intel SSD 660p Series M.2 2280 PCIE 3.0x4 512gb

smirk said:

Intel SSD 660p Series M.2 2280 PCIE 3.0x4 512gb

Click to expand...

The Samsung is about 2.3x faster.
I'd probably put the Samsung in M.2_1 and use it for the Windows drive.
The Samsung already has a 512 MB cache.

Put the Intel in M.2_2 and use it for storage, games, backups, etc.