Panno, what are your other system specs? It usually doesn't make much sense to put a high-end graphics card into an otherwise low-end computer, and likewise a lousy graphics card can be the performance bottle-neck for an otherwise powerful system.
I put an 8800GT in my Quad Core Mac Pro yesterday, and it runs Crysis at 1920x1200 at playable framerates on Vista 32 Bit, DX10 and with 'high' settings. But it's quite obvious that this is as far as the system will go, and I doubt that a better graphics card without a simultaneous CPU upgrade would make much sense.
I put an 8800GT in my Quad Core Mac Pro yesterday, and it runs Crysis at 1920x1200 at playable framerates on Vista 32 Bit, DX10 and with 'high' settings. But it's quite obvious that this is as far as the system will go, and I doubt that a better graphics card without a simultaneous CPU upgrade would make much sense.