Successfully installed a Radeon RX 5700 XT on a Supermicro H12SSL-i with BIOS 2.5. No special BIOS configuration required except one:
Onboard Video Option ROM Enable (DISABLED).
The BIOS at first displayed an UNKNOWN DEVICE in the
Advanced > AMI Graphic Output Protocol Policy
and I changed the Bifurcation setting for the GPU SLOT from
AUTO
to
X16
thinking that maybe the motherboard just doesn't know how to deal with the card. After the BIOS had recognised the GPU I lchanged the setting back to AUTO. Not sure if forcing the SLOT to X16 enabled the motherboard to properly detect the card.
The AMI Graphic Output Protocol Policy now displays:
NAVI10
AMD GOP X64 Release Dri
Output Select DFP3_HDMI
Some more about dealing with GPUs on Wendell's Level1Techs video on the H12SSL varients:
If you are installing Windows he recommends using a JUMPER to disable the Onboard VGA.
Even with the iKVM video output disabled in BIOS the booted Linux Live Installer will list the iKVM display in the iSpeed controller as a Virtual Monitor in the Linux Display Configuration panel. The mouse on the PC remotely connected to the Supermicro iKVM/BMC can be used to drive the cursor on your Supermicro workstation's main display. Linux automatically bridges the two video hardware systems. The iKVM Virtual Monitor can be disabled in the Linux Display Configuration panel.
To me it seems that most cards should work on the H12SSL series, BIOS versions notwithstanding.