I have two Mac Pro '09s which are both running 10.7.5 with NVIDIA GeForce GT 120 512 MB cards. Both have been flashed from 4,1 to 5,1. I've noticed lately that browser windows are starting not to refresh and showing mosaics. This is solved by creating a blank tab and switching tabs, which forces refresh, but I think it's time for a graphics card update. Maybe I'll put two existing cards in one of the machines for multiple monitors and upgrade the second for a 30" 4K monitor. My heaviest graphics use is Photoshop. I don't do gaming but may get in to some 3D modeling. Budget to mid range recommendations appreciated.