Futuremark's 3DMark05
The green graph line represents ASUS EN6800 Ultra 2DT's performance. It's obscured by an RADEON X850 XT's, showing how close these two GPUs are in Futuremark's DX9 benchmark.
Adding in 4x AntiAliasing and 8x Anisotropic Filtering from the benchmark's options doesn't do much to separate these three high-end video cards. In fact, I'd challenge anyone to tell the difference between the three without prior knowledge of which card is in the machine.