Your system is under clocking and under volting. Run a stress test and check the CPU-Z. If you don't like it doing this you can change the CPU Halt in your BIOS under Advanced BIOS Features, CPU Enhanced Halt(C1E). This may help...
mine right now is at 4.2ghz and im at 1.356 i would start a little higher then run the test then if that works bump it down by one click and run again then repeat that so you can find the lowest volts for that OC. i know its time consuming but its really the only way
What happen if the processor have too low voltage?
It becomes unstable and will not boot into Windows or you get Windows BSOD when it does. Just bump the voltage if this happens or bring your over clock down until it is stable with the voltage you set.