All three motherboards support multiplier ranges that exceed the potential of any hardware available today, and all three support high voltage levels that exceed our cooling solution. Rather than tempt fate with some form of exotic cooling that wouldn't represent real-world use, we made this a comparison an average builder can rely on. Sunbeam’s Core Contact Freezer serves cooling duties.
We don’t see any large differences in CPU overclocking capability, but the M5A99FX Pro R2.0’s win is valid regardless of margin. More impressive is the integrated northbridge clock rate, which pushes well past ASRock's effort and hints at trouble for Gigabyte's platform.
That trouble shows up as moderate DRAM data rate limits, since the FX processor’s integrated northbridge operates only at frequencies that exceed the DRAM data rate. Asus widens its lead over ASRock here, at least when two modules are installed.