Unfortunately, we do not see the same close results in the overclocked mode because all mainboards overclocked the processor differently. The following table sums up our overclocking results:
A 100 MHZ difference in resulting processor frequency produces about 2% performance difference. So, 4% performance difference between Asus Rampage IV Formula, which overclocked the CPU to its maximum, and Gigabyte GA-X79-UD3, which stopped at 4.5 GHz, is quite normal, although a lot depends on the test application, of course. There is hardly any performance difference in gaming applications (less than 1%), where not only CPU, but also the graphics card contribute to the overall performance.
It is even more convenient to compare the results of Gigabyte GA-X79-UD3 against those of ASRock Fatal1ty X79 Professional, which managed to overclock the CPU to the same exact frequency. The performance difference between these two systems is around +/– 0.3 %, i.e. is practically missing. Only in Resident Evil 5 Gigabyte mainboard is significantly faster, but it looks like its success can be explained by the suspiciously poor performance of the ASRock mainboard in this particular game. As you can see, minor differences in timings didn’t affect the performance of Gigabyte GA-X79-UD3 in any way.