so i have read some stuff on upgrading the card in the imac 24" and it is pretty much possible... except you would probably want someone certified to do it for you... so lets say after a couple of years that the 7600gt starts to show its age... after all, it is a mid-range graphics card compared to other stuff out there.... hypothetically, couldnt you upgrade it to another MXM card, say the 512mb 7900gs series out there? just wondering what everyones thoughts are on this and if there are other cards to substitute instead.