At their factory speeds, the ASUS RoG Matrix HD 5870 is 50MHz slower than the Gigabyte bad boy, and accordingly this is the fastest HD 5870 we've yet tested.
It's right on the limit of what it can do, though, and still not a match for a GTX 480.
DirectX 10 performance
Anti-aliasing performance (4xAA)
DirectX 11 performance
Benchmarks run at 2560x1600 on the highest settings