Which M.2 slot?

[Chum]

Friend getting a new one and he has 4 places on his board. Does it matter which one?

 

[JLK03F150]

Yes, he's going to need to read his motherboard to see which M.2 slots interact with other things.
Some M.2 slots may slow some PCIe slots and others may disable SATA ports on the board.

 

[EarthDog]

Friend getting a new one and he has 4 places on his board. Does it matter which one?

Depends...but usually putting it in the primary (typically the top-most) M.2 socket is the best course of action.

We have no idea what drive (PCIe....3? 4? 5?) or what motherboard, so it's tough to tell, but the line above typically nets you the fastest socket without lane sharing.

 

[MisterEd]

I agree. You need to refer to the motherboard manual to see what the limitations are.
For example, here are is what it says about my ASUS ROG Strix B550-F Gaming WiFi II motherboard for its 2 x M.2 slots.

 

[EarthDog]

You can blindly put a NVMe drive in the first/top/prary socket without lane sharing/anything disabling.

It's the other slots that may be limited in speed and share lanes. As was said above, you should refer to your manual for clarity in those as it varies by board and chipset.