I just finished putting together my first PC and everything runs fine until I open a game, including Unigine Heaven. I'm new to benchmarking and overclocking and all that, so I have no idea what's happening. My GPU (RX 580) is used from a guy who used it for bitcoin mining and he said he overclocked it. No idea if that's contributing. I downloaded MSI Afternburner and tried to set the clocks to stock levels but it didn't help.
It started when I booted up Guild Wars 2 the other day, played for a couple minutes, and the screen started flickering to black for a few seconds and them coming back. Did that regularly until I gave up playing. Opened Apex Legends to see if it happened there too; it didn't, but the graphics in the training area were all glitched out instead. Tried both again today; the graphics work in Apex now, but the black screen now happens faster and lasts much longer. I can still hear everything.
What I've tried: other than changing settings in MSI Afterburner, I manually installed the latest drivers from AMD. I also loaded that up along with the Task Manager and started the Unigine benchmark. As soon as it opened the GPU load spiked to 100% in Task Manager and Afterburner showed the core clock and memory clock at max. Ran Malwarebytes, nothing found. I have no idea what to do, please help.
Specs: Gigabyte AORUS B450 mATX MOBO; Ryzen 5 2600; MSI Radeon RX 580 Gaming X 8GB; 16GB DDR4-3000 RAM; Seasonic Focus Plus Gold 750W 80+ Gold PSU; 144hz 1080p monitor.
Note: I played both these games before on an old GTX 660TI no problem. What changed since then is the GPU, PSU, case, and drives (from SSHD to SSD). Same monitor, MOBO, CPU, RAM.
Let me know what more info I can give that would be helpful. Thank you!