When it comes to testing really old video cards where 320x240 might actually be relevant (I'm looking at you S3 Virge and SIS 6326) I have an old Star Wars Jedi Knight: Mysteries of the Sith demo that is extremely quick and easy to use. Using that, I have found that almost every pre-2000 3D card I have tried on that system has worked at 320x240 as long as I don't select "Mode-X". The game is also really convenient because I can quickly toggle hardware acceleration to see if some cards are actually decelerators on a specific CPU. No restart required. It also has a setting for colored lighting and "Back Buffer in System Memory" to diagnose some issues.
If you want to try that, download the demo zip here and just use the "MotS Demo":
https://community.pcgamingwiki.com/files/file … the-sith-demos/
I have not tried the higher res textures or sound enhancements... that is something I just discovered when I found this page a second ago. I doubt those work too well on 2MB and 4MB cards. 😀
Now for some blitting from the back buffer.