Graphics Cards

[jocan]

Card1 Label: AX5450 1GBK3-SH

Card1 Label: AX5450 2GBK3-SHV7E

When two installed, BIOS does not see any of them and uses built in display port as primary to display boot messages, etc.

Each one alone works as designed.

Desktop is LENOVO ThinkCentre M920t

Please advise.

[JohWill]

In the bios set your PCIe to a different mode.

some bios have like PCIe mode 2 for dual cards

The correct lanes would be PCIe 2x8 for dual so look up your motherboard manual and find PCIe 2x8 lanes.

you can also do PCIe x16 plus PCIe x1 or PCIe x2 

just remember that desktop only has max 400watts and a low tier card would use 75watts without a PCIe 8pin. Rx6500 etc. a rx7600xt would use 200watts

the two cards would use up to 75 watts each.

I believe those GPUs are 4 to 8 lanes each.  

[jocan]

Thank you for taking your time trying to help. Here is Lenovo PCI configuration screen:

What should I select? Options are Auto, Gen1, 2 and 3.

First two slots are the ones I tried to use, since third one is small.

[goodplay]

Back in the day some motherboard chipset models did not support bridgeless crossfire.

Check with lenovo support if your mobo has support for it.

[jocan]

On another note is there any single AMD board capable of driving two dual link DVI monitors like Tobago PRO [Radeon R7 360 / R9 360 OEM] does but without a need for external power? GPU performance is irrelevant.