My PC has an Intel i7-12700F, 32 GB of DDR4 memory, three SSDs, an RTX 3080, and a Corsair RM850 power supply purchased in 2021. Recently, the system has started restarting whenever I launch demanding games such as Cyberpunk 2077 or Black Myth: Wukong, and it sometimes even restarts while sitting at the desktop. CPU and RAM and power tests in OCCT ran for 10 minutes without problems. I also tried reducing the GPU power limit to 65% in Afterburner, but the restarts continued. I suspect the PSU may be failing or struggling with GPU transient spikes, but I do not have another unit available for testing, and replacement purchases cannot be returned in my country unless the product is faulty. What are the best ways to determine whether the PSU is actually the cause?
2 Answers
Five years old does not automatically mean the RM850 is worn out, but sudden restarts under gaming load can point to the PSU, GPU power delivery, overheating, unstable memory, drivers, or the motherboard. Check CPU and GPU temperatures and look in Event Viewer for critical Kernel-Power events. Also run Windows system-file checks such as SFC, and test with default BIOS settings if you use any overclock or memory profile. The most reliable PSU test is still trying a known-good unit with enough wattage, or having a repair shop test yours under load.
A short synthetic test passing does not completely rule out the power supply out. Some games create different, sharper CPU-and-GPU load changes than a benchmark, and an RTX 3080 can produce substantial transient demand. Check that every GPU power connector is firmly attached and, if the card uses multiple sockets, use separate PSU cables rather than one daisy-chained cable. You can also disable XMP and any CPU or GPU tuning temporarily to see whether the restarts stop.
I had not considered system-file checks or checking the temperatures while gaming. I will test those before buying replacement hardware.