In Far Cry 2, the HD 5770 manages to outrun the reference HD 4870 card but only at 1680x1050 without AA. Both cards are quite capable of spinning Far Cry 2 at 1920x1200, with and without AA. Once you push the resolution up to 2560x1600 with 4xAA, both cards drop below the magical 30 frames per second mark.
Left 4 Dead
The HD 5850 manages to outrun the GTX 285 in every single test, where the highest performance gap was around 20%. Furthermore, The XFX HD 5850 does a good job in keeping up with the Sapphire HD 5870 1GB, which is a nice feat especially considering that the highest performance difference is at 2560x1600 and 4xAA 8XAF, and the difference still amounts to 22%.
The XFX HD5750 scores almost identically to the HD 4850 512MB, lagging behind by a few frames throughout the test.
The HD 5770 does pretty well, and without the filters on, it's 4%-10% slower than the famous HD 4870. Turning the filters on results in 15%-20% difference.