Performance Summary
Each board had good CPU overclocking capabilities, but a few had problems with high memory speeds or low latencies. Here's a quick look at how the FSB capabilities compare.
The GA-X38T-DQ6 provides the best high-speed CPU stability at a measured 1.60 volts, but the Asus Maximus Extreme has the most stable bus. All of the companies "cheated" a little on voltage to trick overclockers into using higher-than-desired voltages for improved stability: Asus and Foxconn were the least offensive with a set voltage difference of only 12.5 mV, but we were astute in making voltage corrections.
Using the slowest result of each benchmark as the baseline, we compared the performance of each board at both default clock speed and the board's highest stable CPU overclock. Most X38 competitors were not able to maintain the tight CAS 5 timings set by previously-reviewed P35 motherboards, so a few benchmarks will favor the one motherboard that could.
The Asus Maximus Extreme wins in average game performance for both overclocked and default speeds, and even correcting for its 0.2% default-speed overclock leaves it leading the slowest board by 1.12%.
Gigabyte's stronger overclock wasn't able to overcome Asus' performance superiority, even though both boards used the same looser CAS 7 memory timings when overclocked.
The game performance difference between X38 Express chipset motherboards only became practically noticeable when every board was overclocked to its maximum stable CPU speed. Will the difference be larger in applications?
