Hello,
I'm currently building a R7 3700x based system and I've run across an issue I've never seen before.
This system doesn't require any significant gpu power, so I've been attempting to save a little cash re-using an old HD 7950 I've got on hand from back in the day gpu mining was a thing.
On first bootup, I had no video. I figured since I'm using a B450 board it must need a BIOS update. So I swap in an R7 1700 I've got and try again. Nada. Ok, so maybe the video card was dead. It's old, it happens.
I swap it for an RX 480 from my personal rig, everything works fine. BIOS is even up to date. So, I try a different 7950, and put the 3700x back. Works, great. Now I disassemble and put it in the case. Black screen. Weird. I check all the connections, everything looks good. Still nothing. I put the 480 back in, and it works again. Swap it back to the 7950, still works. At this point I'm a little suspicious, so I pull the power cord and try again. Black Screen. Try the swap again, works fine until I pull the plug. Turning off the PSU switch doesn't cause a problem, just pulling the power cord.
So. Any ideas? Am I doomed to buying a new card?
Specs:
Cpu: 3700x
Mobo: ASrock B450M Pro 4
Ram: Corsair Vengeance 16GB 3200 mhz
GPU: Sapphire HD 7950
SSD: Crucial MX500