Gen4 m.2 using PCie3 on my z790-E gaming Wifi. Why? how to fix?

[Cainn23]

I have a 4tb WD nvme gen 4 slotted into m.2_2 it's reading a connected speed at PCie 3.0.

I have a  4090 with another 2 tb WD slotted in m.2_1 and its showing 4x4 speeds fine.

Can anyone explain what is going wrong here?

[GTGhigo · Accepted solution]

Use slots 3-4-5 or you also will get GPU pcie drop from 16x to 8X, lines on m2_1 and m.2_2 are shared with gpu.

[Cainn23]

My understanding that my boot on m.2_1 will run 8x8 which is probably negligible with a 4090. Which i'm ok with. may change that one later. 

But you are saying that it's splitting it 3 ways as is since i'm using m.2_2 also?

[JohnAb]

Not sure about your board, but check the manual. On my 690 Hero, the M.2_2 slot only supports Gen 3. 

[drop4205]

Bios updated and intel firmware updated?

[Cainn23]

Yes it was doing it because it was the 4090 and the two  m.2 in slots 1 and 2 are shared.

Moved them both to slots 3 and 4 and all is fixed. Technically it would have worked with the 4090 and slot and 3