ASRock FM2A75PRO4, A10 5800K.

Watched CPU temp in BIOS for a while to check that heatsink was seated properly with even contact to CPU for heat transfer.

Temp started at typical idle (30°C), while checking a few other things in the BIOS menu and taking about 10 minutes doing so - just looking not altering settings, the system froze.

Restarted and watched the temp, it rose from idle temp to max recommended (75°C) in 0.5 steps, changing every 1-3 seconds, I watched this a few times, restarting before it could freeze again.

Then just let it boot into Windows - temps normal and stayed so. Same thing happened with a boot into Linux.

Lingering in BIOS causes slowly rising temp to crashpoint each time. I wonder why?

  • Because in most cases at least a single core is allowed to be fully utilized and as pointed out thermal mangement might be disable but it still shouldn't be crashing. If its crashing then your system is not stable and your CPU is likely throttling itself while in Windows. I would apply the thermal paste again.
    – Ramhound
    May 9, 2014 at 17:21
  • Thanks, checked using conky in Linux with system under full load (video transcode). CPU auto-overclocked to max on cores used, temps within acceptable range for full load). Instability was probably caused by mis-identified RAM. With corrected settings for RAM in BIOS, system alarms and shuts down as per alarm settings. Learned two things: BIOS 'idle' is actually full load and 'load defaults' does not always mean 'load correct settings'.
    – Will Smith
    May 9, 2014 at 17:53

2 Answers 2


Some BIOSes lately are not correctly supporting idle state. Such BIOSes make operations like watching for keyboard operations or presenting updated data (even if once per second) and take full CPU load. While CPU is in 100% use it makes CPU hotter and hotter, then the problem appears.


Most BIOS setups do a busy-wait for keypresses in 16bit mode - with thermal management disabled and often no active fan control. This is obviously the worst case for CPU tempreature.

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