For a 4800X2 the typical OC is in the range of 2.5-2.7 GHz, with some pushing higher. 1.45V is not too high at all. Though I run at 2.66/1.344V, I have pushed my CPU to 1.58V when finding the max OC, and nothing adverse happened. Just keep an eye on the temps and don't break 1.625-1.65V on air cooling.