Overclocking greatly varies due to what hardware is being used and who is doing the overclocking. Always remember that no two pieces of hardware will perform the same, so our results will differ from what you might be able to get.
With Default BIOS settings the Intel Core i7 990X Extreme Edition processor takes advantage of the typical Bclk of 133MHz and uses a CPU multiplier of x26 to reach the final clock speed of 3.46GHz. In the above screen shot we can see that the Intel Turbo mode is in effect and giving the 990X a boost to 3.6GHz. With a lightly treaded application Intel’s Turbo mode will push the 990X up one more multiplier for a speed of 3.73GHz. Since the Core i7 990X Extreme Edition processor is an extreme edition we have an unlocked multiplier that we can play with to increase the speeds!
Just to test the waters with the Intel Core i7 990X Extreme, I left all of the settings on auto and started to increase the multiplier alone. With the ASUS Sabertooth X58 we were able to increase the multiplier to x33 which puts the Intel Core i7 990X Extreme at 4.41GHz! That is nearly a 1GHz boost on auto over the default 3.43GHz!
When all was said and done, we were left with an overclock of 4735MHz! That is an increase of 1.3GHz or nearly 37%! This was done with a multiplier of x35 and a Bclk of 135MHz. In order to accomplish this we had to increase the core voltage up to 1.425V and all other voltages were left on auto. This overclock may have been a bit on the conservative side since I was a little hesitant to blow up a $999.00 processor. I don’t doubt that the Intel Core i7 990X Extreme processor has more to give, the temps were beginning to climb into the 90+ Celsius range and my wallet was starting to cringe!
Once we found a stable overclock we put it through our usual paces. So that we can see what we can expect performance wise from the Intel Core i7 990X Extreme we ran wPrime. At the default settings the 990X turned in times of 165.49 seconds for the 1024 million benchmark and 5.736 seconds for the 32 million runs. With the auto voltage overclock of 4410MHz we knocked just shy of 30 seconds off of the 1024 million runs for a time of 135.674 and the 32 million runs averaged 1.025 seconds faster. Increasing the voltage of the 990X allowed us to fo faster yet, and we were able to knock off an additional 9.159 seconds for a grand total of 38.975 (23.6%) seconds below default! The 32 million runs were an additional .337 seconds faster for a grand total of 1.362 seconds below our starting point!