I recently switched from Windows 7 to Linux and am completely new to this operating system. Although I am convinced by its advantages, an insurmountable problem has come up during this transition.
Both Ubuntu 12.04 LTS and Fedora 17 exhibit brief intervals of normal operation, alternated by periods of extreme lag. The latter are characterized by drop-down lists that barely open, slow switching between programs, buttons that become highlighted only after a few seconds, etc. After some time my radiator roars for 10 seconds, the whole systems accelerates and becomes (very) fast again. Turning off some visual gimmicks doesn't help. My current set-up: Asus N53S, Intel Core i7-2670QM, 2.2 GHz, 8 GB RAM.