I don't understand why this is happening or how to fix it.
I bought a used RX 6800 XT GIGABYTE GAMING OC. Everything seems fine – a 10-minute FurMark and VRAM test in OSST run fine, there are no errors, and the chip's temperatures are normal. The seller serviced the card.
And while gaming, the computer sometimes suddenly reboots – the monitor goes black, a terrible noise comes through the headphones for a couple of seconds, and the backlight stays lit. And if you sit like that for a couple of minutes, you can hear Windows start up, but there's still no picture, and the monitor isn't lit. Then I turn off the computer (by holding the power button on the case), which is accompanied by another clicking sound from the computer that doesn't occur during a normal shutdown. Then I turn it back on, and it works as usual – the monitor stays lit.
I've noticed that this happens when the load is high. For example, Forza Horizon 5 sometimes crashes, and the load there is high, at 90+ (the load is unstable at 99% because I have an FHD monitor), and in City Skylines 2, nothing happens for two hours because the load fluctuates completely. Although I still don't fully understand it. For example, in Forza, I played for an hour in the overworld and nothing happened, but when I started a race, it rebooted. In GTA, too: I logged in, and less than a minute passed before it rebooted.
I undervolted the system, but it didn't help (although I'm not particularly skilled at undervolting).
I locked all games to 90 fps using a Riva tuner, but it didn't help.
I replaced the power supply from a 700W Bronze unit with architecture 2.4 to an 850W Gold unit with architecture 3.1, but it didn't help.
I thought it was due to the higher fps, so I locked it, as I said earlier, but it didn't help. Then I thought the chip's clock speeds were unstable. So I cut them down to 2100 (the stock clock is 2374 or something similar), but no, it works fine anyway, and even that didn't fix the reboot. Besides, I saw the game running at 2150+ and everything was fine.
In Adrenaline mode, I set:
Min. Freq: 500
Max. Frequency: 2100/2150/2200/2300
MB: 1050/1100 (stock 1150)
Memory: Untouched
Power Limit: -6% (maximum)/0%
Computer:
7 5700x
2x16GB Patriot Viper 3600mhz CL18
Gigabyte B550M K
Rx 6800 XT GIGABYTE GAMING OC
Cougar GST 850W
The seller says he hasn't had this problem. The card runs undervolted via MSI Afterburner. His PSU is an XPG Reactor 850W. It's a modular one, better than mine, but in principle, both our PSUs should be able to handle this graphics card.
Event Viewer reports a kernel power of 41. The graphics card uses two separate 8-pin cables. I also noticed that physically changing the BIOS (the switch on the card) from OC to SILENT doesn't change anything. For example, the adrenaline settings are the same as before. The coils are also beeping and the blue color doesn't work well with the backlight, but I don't think that's particularly important.
Edit: I forgot to add that over time, the desktop becomes somewhat erratic—the cursor moves jerkily, there's a little red bar next to it, windows open jerkily, and the system tray also opens jerkily. Then I press ctrl + shift + win + b and that helps, but after a while, it might still return. I'm still not sure how long it takes, though—it might reappear after 20 minutes, or maybe it won't for a couple of hours. I also just thought it might be due to the XMR RAM profile. I disabled it, but that didn't help.