I have to say, I'm a big fan of this computer. I'm new to Apple computers and I've had nothing but great luck with it thus far. I got this one the day they refreshed the line with the speed boosts. However, I just ordered 4GB of memory from Crucial and installed it the other day. Lately I've been ripping all of my dvd's into Apple TV format using Handbrake. This had been working fine ... but since I installed the 4GB, if I'm ripping a movie and then sync either my iPhone or nano through iTunes, the screen will completely freeze up. My mouse will move around for about 3 minutes (unable to click on anything) before it turns into the pinwheel and won't come out of that without shutting the computer off altogether. Any advice?