Which of the 2600 PRO in the iMac and the 2600 XT in the Mac Pro is the better one? I've searched around, and I couldn't find anything on the iMac specifically, only the non-mobile version. So, which one is better? I can't decide if I should get a previous-gen iMac w/ 2600 PRO or current-gen with GT 130. If I know the 2600 PRO is similar to the 2600 XT. then I know what games I can play with the 2600 PRO. Thanks!