It could be a number of things.
But if you ruled out RAM, Temps, Power Supply, Video Card, and Motherboard Issues, " Is this system powered through a battery backup to protect from dips in power that just happen to happen when gaming "?
I have seen people bring me computers that they claim crash on them and they work fine when I get them. They are extremely frustrated that the computer is fine everywhere else but in their home. In the end it is found that their appartment has shady electrical and a neighbor that turns on a toaster, microwave, or vacuum would cause a voltage drop to their appartment and cause the computer to crash due to insufficient power to operate.
ASRock boards are a brand that I avoid. I spend the extra for better boards, but anyways... Is this board still covered by a warranty to swap it out RMA return and replacement?
If it was my system, I'd perform the following if not already done:
#1 - Memtest86 and have it run through at least 3 full tests to make sure that there is no memory issues!
#2 - Download and run yCruncher and stress test the processing of this system. Your CPU temp will spike and you can test to make sure that when all cores are pegged to 100% that its staying below the maximum temp rating for the CPU. Download and install and use Speedfan at the same time with the graph tab to show a temperature log for the CPU, the CPU is sometimes TEMP1 on the list.
#3 - Download and run Passmark free benchmark utility. It will stress the entire system including the video card. The video card temp will get hot during this process and you can log this with speedfan by checking the GPU box to log it, and you can log the GPU and the CPU ( aka TEMP 1 ) at the same time. *Pay attention to the benchmark test process as for it tests by sections, so if it gets to the GPU benchmark and then it crashes the system then its probably video card related if not the power supply dropping out, while if its a memory section of the test then maybe you have a flakey memory stick that is not a completely matched pair.
#4 - Knowing that the power is clean to the computer, I'd swap out the power supply with another power supply as for this power supply may be dropping out after long load durations.
#5 - If you have a different video card to test with, I'd swap the video card out and see if the problem goes away, as for I have seen video cards go out to lunch after extended periods of gaming even with temps in the normal operating range!
#6 - If the problem still exists and memory and power supply are not the issue, swap out the motherboard via Warranty Return. ( *Hopefully its still under warranty!!! ) ASRock has been known to use a mix of good and low end parts in their motherboards to low ball the competition in pricing. Its not uncommon for there to be a component that works most of the time, but fails under stress testing in their boards!
Edited by goldfist, 09 January 2014 - 09:12 PM.