Overclocking
The ASUS X79 Sabertooth offers BCLK strap settings that push up the bus speed from 100MHz to 125MHz, 166MHz or 250MHz. Factor these in with a multiplier and one can engineer all kinds of overclocked frequencies.
Inputting 1.35V in the BIOS - up from 1.1V - and some trial-and-error later, we managed a stable speed of 4.75GHz/125MHz BCLK/1,666MHz memory, all cooled by a mid-pack Zalman CNPS11X Performa heatsink. All cores work at this speed, actually, as we've not passed the four-bin limit with respect to the muliplier used - 38x in this case.
Providing useful numbers to compare against, we overclocked the Core i7-2700K to 4.7GHz (100MHz BCLK) and have put those numbers in the following graphs.
The similarities of the two architectures are shown by close performance at overclocked settings.
Understand that power-draw suffers as voltage is increased. Core i7 3820 system-wide idle power increases from 85W to 132W and wPrime (all-core-load) from 165W to 242W.
If you're interested, under-load temps read as 55°C during stock-clocked tests and 69°C for these overclocked ones.
