I have clocked my 2.0 GHz Celeron to 3.0 GHz, with stable operation for several days now. CPU temp is about 40-44 C when loaded, lower otherwise. I am running it in an Asus P4PE, a fabulous mobo for us clockers. I have done little for extra cooling. I added an 80mm case fan, installed backwards (to blow INWARD) at the rear of the case, blowing right across the CPU. I also added a PCI exhaust blower, which is a nice thing: very quiet and amazing airflow. A blower (squirrel cage fan) is very efficient compared to a "propeller" style fan. I've positioned it to draw air across the video card on its way out.