you say divx and sutch.....
are you watching H.264 or X.264 encoded movies.... it is my understanding (Please correct me and teach me how) that x.264 is not possible to get hardware supported playback. So what you need is not a powerfull GFX, but a powerfull CPU.
If you are playing H.264 there is allot of cards out there that offer HW accelerated playback.
//Jan |