windows XP Media Center compatibility

i have a sony media center computer and i am interested in changing the video card to something that other apps can use but i am having a tough time finding a compatibility list. does anybody happen to know where i can find some sort of listing of compatible hardware?

M$ seems to be pretty tight lipped about compatibility info as far as hardware goes. i have looked around thieir site a bit but it seems to be of little help so i was hoping someone here could help out.

peace,
dumwaldo