I recently changed my mobo to M5A99FX Pro 2.0 for a better OC and SLI support, and I was able to make it stable @4.8GHz, passed Prime95 tests for half an hour, and has been running games like BF4 and watch dogs completely stable. Yet, upon start up and other occasions where the CPU is at almost 0% usage, the screen often just freezes with no BSOD or power off, or restart, etc. It just freezes. After that, if I press the reboot button on my case, the screen would go black and will not turn on at all. Only if I turn off the PSU and turn it back on, then my computer turns on completely normal. I went on checking the event viewer and did not see anything. The point is that almost ALL freezes occurred when the computer is idle instead of under load. I even had games open overnight several times just to test this, and the computer was completely fine the next morning. I tried to change BIOS settings on CPU voltage, power supply phases, etc, and refreshing the BIOS, none of which worked. When I was on my old motherboard (a MSI 970A-G43) I was able to OC to 4.6GHz just fine. I wonder wat is going on with my PC.