I recently started work on building my retro machine (will make a post once it's ready) and I'm looking for help/suggestions on the following issues:

-Drive bay
I bought the case used/secondhand; wanted the smallest possible case and this is what I found... Codegen SP 3D19-CA
The 5.25" drive bays have huge holes on each side, making it useless to put screws in the drive. I have a feeling I'm missing some part that originally came with the case... maybe?

-GPU glitching
While the machine will run mostly on another card, I bought this MX440 in case I need something more compatible or period accurate.
Unfortunately when I booted with it, there's glitching all around. Reading and searching, all seems to point to bad VRAM; however before I return it I thought I'd ask if maybe there's something I'm missing or something I can test to be 100% sure that's the issue (I tried 3 other GPUs and they all worked fine).
Mobo is a Soyo SY-7VCA
PSU is a Segotep ATX-500W (23A on +12V, 30A on +5V, 30A on +3.3V, +5V&+3.3V 180W(MAX)

Hope I didn't miss any essential details, but will be happy to provide any additional information required.

Thanks.