So I have read all of the threads and I am still at somewhat of a crossroads on my overall desktop setup. For the past year I have been running a GTX 670 in my Mac Pro 4.1 2.66 quad core with 32gb ram. When I bought the GTX 670 it was right when Apple started adding all the additional GPU support etc. Well once the smoke cleared and Abobe CC and FCP X 10.1 updated, either really played well will the GTX670. Especially Adobe even with the hack to get Premiere Pro and After Efects to recognize the card for the mercury playback engine. With that being said, I just sold the 670 and now am debating between the GTX 680 or looking into one of the quatto cards. (New or used in a comparable price range) It seems rendering has just been getting slower and slower as they release newer verisons on the software I also wondering if it is maybe even time to replace the Mac Pro all together? What are ya'll thoughts of continuing to throw money at a MP 4.1 at is only a quad core 2.66 to start?