I have a GTX 570 2.5GB (from MacVidCards) in my Mac Pro 4,1. After months of flawless use with 10.8.2, I updated to 10.8.3 and CUDA 5.0.45 yesterday and now I have problems. In Firefox and Safari, there is occasional horizontal tearing when scrolling quickly. After Effects still recognizes the card but it's hiccuping and freezing when using CUDA. Guess I should've waited for a Nvidia driver first.