Jumpexx

Hey all, first time dealing with a non-startup crash so apologies if this is basic. My rig randomly hard locks when I'm basically doing nothing: on desktop, reading PDFs, sometimes overnight. Screen freezes, audio buzzes if anything was playing, power button is the only recovery. But I can loop Cinebench and OCCT for an hour without a crash. Temps fine. Is this some kind of idle power issue? I just updated to the latest chipset driver and it still happened. Specs are Ryzen 5 5600, B550M DS3H, 2x8 Corsair LPX 3600, RX 6600, Corsair CX550M. Any starting points?

Sounds like classic idle lock. Check Event Viewer for WHEA 18 or 19. If you're seeing Kernel-Power 41 only, that's just the OS saying 'I didn't shut down cleanly', not the cause. I’d start with C-states and PSU idle control in BIOS. Also RAM at XMP can be marginal and only bite when the fabric downclocks/idles. Are you on a recent BIOS?

Ooh I chased this exact thing on a compact build! It had me pulling my hair out. My money is on the low-power state, especially if it's truly idle-only. Have you tried disabling Global C-State Control and setting Power Supply Idle Control to Typical? On some B550/5600 combos the voltage/frequency drop at idle causes a freeze. It’s not a fix, but it isolates it in ten minutes. Also, check if your motherboard has an old BIOS from before the Ryzen 5000 fix!

Welcome. The pattern you're describing — clean under load, lockup at idle — usually points to a low-power state transition rather than a thermal or heavy-current problem. Under all-core load, the CPU stays in higher P-states; at idle it rapidly enters/exits C-states and alters voltage/frequency. A marginal PSU or motherboard voltage regulation at near-zero load can occasionally drop out.

Start with these BIOS changes, one at a time:

• Disable Global C-State Control temporarily.
• Set Power Supply Idle Control to Typical Current Idle.
• Leave XMP on initially, but if it still freezes, test with XMP off or manually loosen to 3200 MT/s for a few days.

If it doesn't recur after a week, re-enable C-states and test only PSU Idle Control. I had a Gigabyte B450 board that would black-screen at idle until I set typical idle; it later turned out to be an older AGESA bug fixed by a BIOS update.

Thanks everyone. So I checked Event Viewer — I have a bunch of Kernel-Power 41 (63) entries but no WHEA logger entries that I can find. I went into BIOS and set Power Supply Idle Control to Typical and disabled Global C-State Control. It's been about 5 hours with no freeze, which is promising, but I won't trust it until a couple days. One weird thing: my CPU now sits at 3.5 GHz in Task Manager? Maybe I'm confusing myself. Do those settings disable boost?

Nah those settings shouldn't disable boost. Task Manager is garbage for clock readings anyway. Use HWiNFO and look at 'Effective Clock' under load. If you’re actually stuck at base, check if you clobbered Core Performance Boost or set a manual ratio. Also, if you’re on the original B550M DS3H BIOS, flash to a recent one — Ryzen 5000 support was rough early on.

YES, HWiNFO! And don't panic if effective clock drops at idle, that's the point. But if it won't boost under Cinebench, something else got changed. Have you tried resetting BIOS to optimized defaults, then only changing one thing at a time? Because if C-states are off and PSU idle is typical and it still locks, I'd point hard at RAM. Those 3600 LPX kits can be stupid about idle fabric transitions.