I bought my RX580 off amazon about a year and a half ago, and it worked fine up until about six months ago. My RX580 has been having periods of crashing my computer in which the screen turns a random colour, normally blue or black, for a few seconds, and then the screen turns off, my monitor doesn't receive signal and my fans spin very quickly. The only way I can then shut off my computer is by holding down my power button on my case. In order to temporarily fix this problem I have repeatedly had to both disconnect my GPU cable and reseat my graphics card in my motherboard following me booting it up without a graphics card and then rebooting with it back in. Also, when I try to turn on my computer following a crash my peripherals (keyboard, mouse etc.) don't light up and I either manage to boot into my computer and it posts, but not for longer than a minute before crashing again, or it doesn't even post. I know it is not my RAM or my power supply, or an overheating issue. My graphics card stays very cool (normally below 70 degrees Celsius) when doing most things e.g playing games. My computer also crashes when not playing games, and it normally happens after I perform some sort of action such as alt-tabbing or simply clicking. I have installed and reinstalled multiple sets of older as well as newer drivers as well. I would appreciate any help I could get as the periods of crashing are getting more and more frequent to the point where it is difficult for me to use my computer.
What radeon version are you running?
Try setting the radeon software to standard and see if that helps and turn off anti lag and other stuff and have it with no extras just to see.
I have been running standard since it started crashing out of fear that it could be one of those features which is causing it. I am currently still running 21.5.2 as my drivers, but I've tried moving up to 21.6.1 previously and there has been no difference with the crashing, I've just stayed at 21.5.2 as I've seen some people experiencing problems with 21.6.1 and don't want to risk any further problems. I'm happy to try anything else if you have any other fixes in mind.
If it helps, my graphics card has now started crashing my computer mainly when playing gpu-intensive games. I've been getting away with playing cpu games e.g Minecraft, but when playing Rust or R6 I crash relatively quickly. Also, for the first time, whilst my computer did the iconic turn a random colour and then show no display, this time it did not crash my entire computer as I was able to talk to my friend on discord whilst I had no display. However, after unplugging and replugging my HDMI cable and also unplugging and replugging my GPU cable no display showed. I was left to resorting to restarting my computer again.
Here are some videos showing what happens - on Apex Legends and Rainbow Six Siege. It seems like an overheating problem but throughout those clips none of my parts got remotely hot (GPU below 70 degrees C, cpu below 80 degrees C). Ignore the no back panel on my computer - that's temporary as I just reseated my graphics card.