You're missing power supply and case - the PSU is important in issues like this, and the case helps determine if your machine is undercooled. Also that's a strange setup - a Sabertooth motherboard with a low-voltage CPU?
For now I suggest running stress tests and see if you can reproduce the problem, I'd start with a GPU stress test but you should do CPU as well:
Overclocking tools of the trade
For the GPU stress test, get MSI Kombustor from the link above, run for at least 1 hour and monitor your temperatures.
For the CPU stress test, IIRC you can get a utility from Asus to monitor temperatures, then run LinX for at least 1 hour and monitor the temperatures.