Getting Our Core i7-3930K To 4.6 GHz
We began our CPU overclocking by setting what we felt was a maximum safe voltage, and then trying to find the highest possible stable frequency at that voltage. Jumping up to the 47x CPU multiplier created instability, as did choosing a 101 MHz base clock with a 46x multiplier. We had to settle for a flat 4.60 GHz.
While our memory’s XMP-1600 CAS 8 profile worked as intended, ASRock’s X79 Extreme4 automatically loosened timings when we increased the memory multiplier beyond its XMP rating. This allowed us to choose DDR3-2133 with minimum fuss.
After a few sessions of stability testing, we were able to manually tighten some of the memory timings that the motherboard had automatically relaxed in response to our higher data rate. The board selected 11-11-11-32 timings at DDR3-2133, but we found latencies of 10-11-10-24 to be stable.
Getting to CAS 10 was important to us, since CAS 11 would have resulted in a slightly slower-than-rated response time. Since DDR3-1600 CAS 8 and DDR3-2000 CAS 10 have the same response time, our memory tuning efforts should increase both bandwidth and quickness.
Though we weren’t able to push our CPU frequency higher than 4.60 GHz, we were able to save some wattage by backing down our voltage selection to 1.32 V.