http://arstechnica.com/hardware/news/2009/07/review-nvidia-gtx-285-on-the-mac.ars Looks pretty good. It definitely beats the 4870 in windows gaming, but CoreImage-based and other pro apps on OSX can favor the 4870 because of Nvidia's crappy drivers. Based on prior performance, it seems like Nvidia really hobbles the OpenGL performance of their non-Quadro cards, but this may not be the case on OSX. (I'm a traditionally windows guys). Overall, we need a far more comprehensive test with a multitude of real-world video/graphics/3D/media/etc applications to really know. Most importantly, because of the huge variance in performance, if you are looking at these cards with a certain application or applications in mind, I'd definitely wait for a review of said application to find out which card will be best.