If Mirror's Edge or Batman utilizes DX11, that could be why. DX11 hurts your frame rate more than DX9/10.

Oh, and I know that Dirt 2 uses DX11, but it might not utilize it as much as other games.

I need to know more about how these things work .. XD

Batman Arkham Asylum disables it's AA features if it detects a non Nvidia card .
Mirror's edge seems to run a whole lot better if Physx is disabled . I read somewhere that it utilizes the cpu ( which has poor multicore support ) for Physx support for non nvidia cards .

You can thank the Nvidia marketing team for that one. Need 4 Speed: Shift has the same problem, as does any game that artificialy relies on proprietory PhysX instead of the industry-standard, OpenCL. It can be made to run on ATi cards but only with ugly driver hacks to fool Nvidia's software.

Nvidia dont mind fragmenting the PC gaming market, confusing users, frustrating developers, and being anti-competitive, just for the chance to sell you some shitty Nv card.

Physx was kinda cool , it's such bummer . ATI doesn't not something similar to it ( as far as I know ) , they are also pushing n 3D gaming , which requires a panel to have 120 hz support ( or something ) , It would be nice to play and watch videos without those darn glasses .

Yeah they do, OpenCL. And its open, any vendor can use it and any developer can write against it. And unlike PhysX the other major API Havok has been re-written to run on OpenCL and can take advantage of which ever brand of GPU or CPU is optimal. Nvidia apparently considered porting PhysX, but they dont care about playing nice, only making money off you.

Hmmm you could give it to me ;) :D :D :D

heh heh .. bago pa naman eh... mag fermi ka na lang ! XD

ayoko T^T XD

For a start I'd recommend get rid of Vista :P (yeah, flame me plz ^^ )
Now, here's what I know (I'm no VGA pro, keep in mind plz):
Physx is a nVIDIA software thing, so even if ATI cards are compatible (I haven't seen any that are, but I don't really look for any, so what di I know :P ) they should preform a bit worse than nVIDIA cards.

Tried the ATI 3D settings? You know, where you setup the graphical detail the card is set to process. Sometimes you need to enable extra stuff to get better performance or better detail...maybe there's some option there for the Physx thing.

I personally use the 4570 Mobility Radeon, which does not support Physx, but I have a pretty high framerate on Mirror's Edge...don't really know much about the ATI 5xxx series, so other than this I cant give any other advice.

that worked for me , thank you ! now Batman AA looks much better and faster now ! :)

Glad I was of some help ^^