I have a Mac Pro 1,1 2.66Ghz with the 5150. I just ordered a pair of Xeon 2.66 5355's. The system has 8Gig memory, and an 256GB SSD, with a 7300GT graphics card. I mainly use the system for internet browsing, Video Rendering, iTunes, Large Data Mgmt.. How much of an improvement in performance will dropping a Radeon 5770 into the system? I understand it will allow me to use additional monitors but im really just wondering if its with the $250 from a pure performance aspect.