Graphical Benchmark Results
The graphical benchmarks were conducted in SLI mode with a pair of 6600 GTs, using NVIDIA's 66.93 driver. 3DMark05, Doom3 and Half-Life 2 are the tests of choice.FutureMark 3DMark05

The DFI noses ahead by a margin of error (less than 1% variance).
Half-Life 2

A 1% lead sees the DFI beat the ASUS in the Battle Of Stock Clocks.
Doom3

Toss a coin.