My computer is crashing when the CPU is put under 100% load, but not when it put under 90% load.
The components are:
- CPU: i7-4790K (not overclocked)
- Heatsink: Cooler Master Hyper 212 Evo
- Motherboard: GA-Z97X-UD5H
- PSU: A gold-rated 450 W Rosewill.
- No graphics card.
- 1 SSD and 1 HDD.
I am on 64-bit Windows 7 Enterprise.
I am controlling the CPU load using Windows Advance Power Plan settings, by changing Maximum processor state under Processor power management.
After setting the maximum power state to 90%, I run Prime95 with the maximum heat torture test. This pushes all 8 threads to 100% usage (actually 90% because I've throttled it), and my CPU temperature goes to 95C with 123.5 W of power (CoreTemp 1.0 RC6). The system appears to be stable indefinitely like this.
If I set the maximum power state to 100% and run Prime95, I immediately get a crash. The computer does a hard reset without any error message, automatically starts again, and Windows warns me about an unexpected shutdown.
Doing the last experiment almost always results in a crash (at least 95% of the time). The crash is very fast: If I start from an idle temp of 35C, there is not enough time for CoreTemp to update the tray icon. Compare to the 90% case: Temperature takes 2 seconds to reach 85C, and then about a minute to reach 95C.
Needless to say, unless I use Power Options to restrict maximum usage to 90%, I end up having the computer crash occasionally, corrupting data and leading to loss of work (besides being very annoying).
How can I determine what causes this problem?
EDIT: After updating my BIOS from F6 to F8 (latest), the issue has not been resolved.