As I am still trying to get my computers to work with a dual seat (or multiseat), I did an attempt in using the onboard video (a relatively decent Matrox card.) So I went in the BIOS and changed the setup for the video from Offboard to Onboard. Big mistake!

The video stopped working. On reboot the computer beeped 8 times and booted the OS normally (I have SSH setup so I could access the computer, but absolutely no video on either port: on board and off board.)

I have a Supermicro X9SCI/X9SCA. Searching for "no video" or "missing video on boot"... returned nothing usefull.

There were two things:

1. Selecting the Onboard forces the system to use the onboard video even if a PCI vodeo board is available.

2. If the Onboard jumper is setup to turn off the onboard video, then the onboard video cannot be selected (it is completely turned off!)

The big problem here is the fact that the BIOS does let you change that flag without testing whether the onboard video is available...

The main problem I have is that my PCI video board is an NVidea Quadro 600 which runs using a PCIe x16 slot and that's totally incompatible with the onboard video... so I cannot run both at the same time. It is incompatible at the hardware level (don't ask me for details... I do not understand the real problem.)

So... now I had the BIOS setup on Onboard and on boot I was getting 5 beeps and no video. What to do?

I opened the box, removed the nVidia card (Quadro 600). That did not help.

I then remembered there may be a switch/jumper. Sure enough! Next to the legacy PCI slot, there is a jumper that says: enable or disable onboard video. I had to move it to re-enable the Matrox board. The following boot worked!

There is a copy of the whole board from the board manual, the jumper A on the left is the one we're concerned with:

The following is a zoomed version of the JPG1 jumper. You'll notice the instructions right above it.

As a side note I tried NVRAM against this board and found out that both of the computers I have with the exact same configuration generated a completely different output. Not only that, once I fixed the setup to use the Offboard video, the NVRAM output was exactly the same as when the Onboard selection was set. In other words, NVRAM did not work at all for this motherboard.  Also the coreboot system did not seem to help in any remote way to determine anything in link with the BIOS.

So that means NVRAM is not really up to date for all BIOS CMOS memory handling.