I use a IR gun. mine with it OC'd @ 33mhz, @ Full load never got beyond 150 degrees, I used a silver thermal grease, and 2 thin long heatsinks.

Also keep in mind, with the lid off there is no airflow. the ventilation fan only works when the case closed.

to attach the HS to the cpu, i use a little dab of GOOP(e6000) on the very tip of all 4 corners of the cpu.

you can also use artic silver 2 part compound, or jbweld. again I like hacks that you can reverse.

Goop is strong, but can still be ripped off.