I recently developed a problem where my PC will black screen and reboot while under load. Along with this issue is an audible buzzing from the PC. Initially I blamed the Vega 56 I installed last October, as upon restart I would get an error message that my Radeon settings had been returned to default due to an "unexpected system error". But after pulling my case door off and laying the PC sideways on the desk while gaming I've determined that the buzzing is from the PSU, a Corsair HX850. The problem was random for a while, but eventually got so bad that I couldn't even game. Upon reaching the menu/splash screen for AC:Odyssey, the game would attempt to get into the main menu and instantly black screen. No buzzing was audible until it began to load the main menu. I thought it was an issue with AC:O (it wasn't; while I could load and play other games, they would crash within 5-10 min as well) and after a lot of troubleshooting I was pointed towards limiting the FPS via the in game menu, and later on via the Radeon drivers itself. That basically solved my problem- limiting FPS to 60 or 75 (max refresh for HP Omen) allowed me to play AC:O again. However, I still have an audible buzzing while under GPU load, and continue to have a surprise reboot once every week or two. I'm assuming the buzzing is coil whine, and it doesn't bother me as it isn't that loud, but the reboots do. Unfortunately I don't have a spare PSU to try out at the moment. I'm not opposed to buying a new one for testing purposes, but at the same time I still have 3 years of warranty on the HX850. I'm living with things as-is for now, but getting closer to contacting Corsair and attempting to take advantage of their cross-ship RMA option. Before I did that though, I wanted to ask [H] to see if I've missed anything. I was operating with a mild overclock on my 1700X and fiddling with overclock/undervolt on the Vega56, but reverted to stock for both when AC:O became unplayable. Using a power meter I'm seeing about 400W during gaming so should be well within parameters for the HX850. I run a Cyberpower 1500 UPS between the wall and the PC, but that's bypassed for now with the power meter. Is it time to contact Corsair- or is there something else I need to consider?