Batman: Arkham Asylum is an action-adventure stealth video game based on DC Comics’ Batman for PlayStation 3, Xbox 360 and Microsoft Windows. It was developed by Rocksteady Studios and published by Eidos Interactive in conjunction with Warner Bros.
For our testing we set everything as high as it would go, except for Physx and NVIDIA AA.
As you can see here, all 3 cards are topping out around 62fps, which is what the game is limited to without tweaking the configuration.
At 2560×1600 we can see that the XFX 4850 1GB falls behind the higher clocked 4870 and 4890. 30fps is still playable on this game but if you are planning to run this resolution you will probably want something a little faster.