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Rog strix z790-i gaming wifi

MeaCulpa
Level 7
Is it possible to force graphics card to run @ 1 x PCIe 5.0 x16 slot, if both M.2 slots are populated ?

Basically I want to know if I can set the m.2 2_2 slot to use the chipset lanes through DMI for storage,
and keep m.2 2_1 for my boot disk using 4 cpu lanes then have my GPU on the remaining 16 lanes.

I am not sure how to configure the BIOS to do this, as everything I try stops the GPU from displaying
anything and forcing me to use the reset bios button to get my display back on.
1,163 Views
2 REPLIES 2

xnd3r
Level 7
You can have the following config:

  • GPU @ PCIe 4.0 x16
  • m.2_1 @ PCIe 4.0 x4 from chipset
  • m.2_2 @ PCIe 4.0 x4 from CPU


To do so, you need to set PCIe Bandwidth Bifurcation Configuration to X16 mode in BIOS. This can be found in Advanced->Onboard Devices Configuration

By default, if you plug any SSD in m.2_1, it will use 8 lanes from CPU, even if your SSD is PCIe gen 4. By changing the above mentioned parameter you will switch m.2_1 port to chipset. m.2_2 will always use 4 lanes from CPU, so it is a preferred option for boot drive.

DanyB
Level 8

I have this board, m2_1 share bandwidth with PCIE(G5). If a ssd is installed in the m2_1 slot, both will run at 8x, but don't forget its pcie 5.0 by default. So plenty of bandwith for both pcie5.0 ssd + pcie 4 16x GPU. You can also set them to pcie 4 in the bios.