So sorry to hear that...
It seems like a VRAM issue, but it will be a pain to identify which IC is affected.
Sometimes, when the IC is shorted, you can detect the bad one by measuring the heat (the problematic IC will be hotter than the rest). Unfortunately this is not always the case.

I'm not having much luck, am i? 😖
Thanks for the tip, I'm taking it to my friends place to get looked at, he's a tech wizard, but doesn't work on PC parts much, so I'm trying to gather any info I can.

Yeah, you truly are unlucky...
I actually had a similar issue with a Voodoo 2 video card and after many weeks of debugging I literally ended up blindly picking a group of four VRAM ICs and replacing those (I did know that the second TMU was affected, though). Luckily, this solved the issue and the video card has been working perfectly for the past 2 years.

However, I don't think I would dare doing the same on a Voodoo 3 (the IC pins are much smaller/tightly packed). I don't have the skills or the right tools for that 😀

Do you know of a cheap vram donor device? I've been trying to find something with the same ram chips, but not had much luck yet. My friend definitely has the skills and tools, but that doesn't help if we don't have a donor.

The Voodoo 3 3000 typically uses 6ns SDRAM ICs (which makes it capable of achieving 166 MHz speed).
You should be able to find this type of memory on very, very cheap GeForce 2 MX200 cards (in my country these are basically free).
Of course, you could also use higher speed memory from cards like a GeForce 2 MX400 (which will be either 5 or 4ns).
Just make sure that the ICs physical size is identical (there are multiple form-factors for SDRAM ICs, although the one found on the AGP Voodoo 3 3000 is definitely the more common type, used on countless devices in 1999/2000).

That's brilliant news! Only problem is they all seem to be 4 chips and 32mb... I guess that wouldn't work then. I'll keep looking, but if you have some links, maybe you could send then by pm?

If you underclock the card does the problem go away or reduce?

RockstarRunner wrote on 2020-11-08, 14:23:

That's brilliant news! Only problem is they all seem to be 4 chips and 32mb... I guess that wouldn't work then. I'll keep looking, but if you have some links, maybe you could send then by pm?

Indeed, you are right! It does seem like it's impossible to find 2MB ICs on the GeForce 2 MX (or even on older cheap Riva TNT2 M64 cards).
Not sure how a Voodoo 3 would behave with higher capacity RAM, but I imagine that it probably won't like it.
In this case, the best bet is probably hunting down various part numbers that commonly appear on Voodoo 3 RAM ICs and hoping to find one of them on eBay.

Well, I'm going to find out, picked up a card with 8x8MB chips for €5. Speed and bit-wise the same as the V3.
My friend said it might work, as the higher capacity chips just have more address lines active. It can't make things worse at least 🙄

Good luck! Let us know how it turns out 😀