Hope Im not threadjacking, but I installed the 8400gs from xfx...tight fit, seemed to work ok, but my comp will lock up if its on for a significant amount of time(10-15min). No reboots, only lockups. I assume this is heat related and not power supply related(which would induce a reboot). Has anyone else had this problem? What are normal temps to expect from cpu/mb with case closed? Thanks