Troubleshooting a broken GPU.

[Enresshou]

I saw someone selling a broken R9 290 (reference cooler) on Craigslist for pretty cheap. I've been looking to tinker around with computer stuff for a while, so I figured it was worth the gamble and picked it up. Now I turn to you guys, because you know a fair bit more than I do about electronics and PC repair, to help me diagnose the potential problem.

With the broken GPU installed, the computer will start up (all the fans spin, including those on the GPU; no beeps/LED codes from the motherboard) but will not output video. It apparently does this on multiple computers (this is what the seller described it as doing) and I know it's not due to my setup as the system runs perfectly with my 970 installed. I've tried updating/reinstalling AMD drivers, but no luck on that front.

My (relatively uneducated) opinion is that it's possible the guy cooked the GPU, as I know these coolers are prone to running very hot and there's a putty-like substance over the core that seems like it could have been from thermal pads/attempted install of an aftermarket cooler. I'm not sure how to further diagnose this problem, though, so any input would be appreciated!

 

[PatrThom]

That's usually what it is (cooked GPU) though it could also be a bad BIOS flash or some kind of electronic mishap.
A GPU which is going bad (but not yet gone) will often work fine at the desktop (perhaps with an occasional graphic artifact) because clock speeds are often lower in 2D mode than in 3D mode.
A GPU with a failed BIOS flash might not work at all, not even putting up the VGA BIOS message on boot.
A damaged board can be hard to diagnose because it could mean combing the entire surface of the board looking for a broken component, etc.

If you have sufficient power cords and PCIe slots (and room!), you can try and install both cards to see if the computer recognizes the second card at all, or if your power supply is not beefy enough you can run on CPU integrated graphics to do the same thing (assuming you have integrated graphics). If the card is not seen by your computer (in BIOS/EFI, in device manager), then it's probably toast. There are other things you can do to read the actual power being drawn by the card, but those would require equipment you may or may not have.

As a general rule, a GPU is not something you buy for parts. They're dead or not dead, and that's pretty easy to tell apart.

--Patrick