Not software but sometimes if you cool a faulty chip with ice spray it'll work normally as long as it's cold. Maybe that way you can find the faulty chip?

In some (rare) cases you can identify bad chips by probing and measuring the resistance to ground of all address and data pins. With this primitive method i almost repaired a GF3Ti200 from Abit, it was showing artifacts and the PC would completely lock after installing the Detonator drivers.

It's time-consuming, needle probes are required and success is not guaranteed. But being very fond everything Abit-branded, I took my time and found one of the chips that showed a much lower resistance to ground on four data pins (DQ8 to DQ11 iirc) - around 200Kohm instead of the expected 1.5Mohm. Desoldered the chip, tested again to be sure that the fault wasn't in the GF3 chip (it wasn't, all DQ pads had identical resistance to ground after removing the RAM chip).

After transplanting a identical, known-good chip from a FX5200 the card became usable (no artifacts, 3DMark stable), but only with significantly lowered clockspeeds of 120MHz (GPU)/150MHz (RAM) . Previously the "lo-speed" BIOS wouldn't coax the board into working, so I consider it half-repaired. I started replacing all the remaining RAM chips, but it's proving to be a PITA. I have some experience in drag soldering, but the small SMDs bordering the RAM chips are making the task much harder than it should be, and solder bridges are giving me a hard time.

I wish I had more knowledge of electronics, so treat the following as a wild speculation - I'm guessing the RAM chips can fail in multiple modes, and one that shows significant deviation from "external" parameters (like the resistance from data pin to GND) probably has damage in the I/O section (buffers?), but even if a multimeter check raises no suspicion there could be some damage deeper in the chip (individual memory cells?). I'd like some insight on this from guys familiar with inner workings of the silicon 😀

Lastly, I'm not so optimistic about the card being able to run at stock speeds even if/when I manage to swap all the RAM chips - from what I've read, the GPUs themselves go bad sometimes, and in my experience the GF3/GF4Ti series run quite hot regardless of the cooling solution.

I've got a few cards with bad ram I'd like to repair, and I already know I suck at drag soldering so I bought a hot air rework station. While I have fixed a few chips in the past using drag soldering, de soldering is a whole other ball game.