many have had the same issue...lots of threads about it too..
what has worked for most is to use a tool like AnTuTu CPU Master and set max to 1512Mhx and Min to 384 Mhz (set on boot). At least set Min...this has stopped my random reboots.....the OC to 1512 makes things a little faster and smoother.
When I use SetCPU, I am only allowed to set the speed for a max and a min. I thought I was able to set the max and min for two cores and not just one. Any idea what I might be on about?