Pop quiz!
Can anyone think of a reason why a GPU would suddenly kick its fans up to 6000rpm (hair dryer volume levels) and park itself there permanently?
Short story: I have a AMD 6950 GPU that has behaved well for the last 10 months. It's seen very little use over the last 6 of those months, as I've been away from it most of the time. While web browsing last night, the fan started accelerating until it hit max speed and it stayed there. No changes to the GPU drivers or fan speeds were being made. Checking the temps in CCC, Afterburner, GPU-Z and HWMonitor all said the same thing: that the fans were at max speed, but the GPU temp was only in the 40C-50C range. AKA, no reason for the sudden increase in fan speed. To make matters worse, the fan speed refuses to be changed. I can set it manually to any fan speed I like, but it won't slow down. I can set it to auto and it will read something like 24%, but will still be working at 6000rpm.
I shut down the machine, rebooted and all of that over the course of the next couple of hours. I've left it off for several minutes with the PSU shut off. I flipped the built-in bios switch (AMD reference GPUs have dual bios, in case one becomes corrupted) but no difference. I removed the GPU, inspected it and took the compressed air can to it, reseated and booted. Same story. Sometimes it would start quiet and act normal for a few minutes, but eventually it would turn into a jet engine again.
I've started the RMA process, but if there's a fix I haven't figured out yet for something like this, I'm all ears. I can't think of anything that would cause this. The GPU is NOT overheating, but the fans are going to max. I have no idea what could cause a fan to go to max and be totally unresponsive to commands to slow down.
If anyone has an idea, it's welcome. I'd rather NOT be down on that computer for an extended period of time, and I'd rather not have to RMA something that's not broken.