ubuntu 21.04 keeps freezing. need help diagnosing

Solution 1:

BIOS

SuperMicro x9dri-ln4f+ (note the corrected model #)

You have BIOS 3.2, dated 03/04/2015. There's a newer BIOS available, version 3.4, and can be downloaded here. Type "x9dri-ln4f+" into the search box. There's also a new BMC firmware "R 3.48" download.

Note: Confirm that I have the correct web page for your model #.

Note: Have good backups before performing the updates.

Update #1:

Added a Nvidia 710 video card, and so far, no freezing. This makes the MGA G200eW WPCM450 video card suspect.

Update #2:

It looks like the MGA G200eW WPCM450 video card is having a problem with Wayland.

We edited /etc/gdm3/custom.conf, uncommented this line: #WaylandEnable=false, saved the file, then rebooted.

So far no freezes!