Hi everyone. I have a MBP early 2011 with AMD RADEON HD 6750 1GB, and I've been noticing a problem for a few months. I think it's some kind of GPU problem when rendering the screen (it occurs when changing spaces or moving a window), but I'm not sure if its normal or I should ask for a replacement; since it doesn't seems to affect the performance, but it's very annoying when working with Photoshop etc. It's like the image gets frozen and doesn't render smoothly if I'm moving it... And it seems to occur in "horizontal stripes"; I mean, there are some horizontal areas where always happens, and others where it doesn't. I've recorded two videos, since I don't know how to explain what happens! https://dl.dropbox.com/u/1209521/PantallaMBP_video1.mov https://dl.dropbox.com/u/1209521/PantallaMBP_video2.mov Any idea? Thanks!