I have a Dell 1464 and installed Ubuntu on an External drive. After using ubuntu, I realized that a section of 3 or more hours make my screen go pixelated (Actually the blend of colors seems to get distorted and looked hideous). I use ATI Radeon Mobility HD 5450 and have installed the required driver. I'm new to linux.
I'm using ubuntu 10.10, fglrx 2.8.780-ubuntu2
Notice the dark area behind the guy. The color seems to get distored.