Ny_driver, it's possible that either the cooler or the IHS may not be completely flat. Surfaces that are convex/concave will prevent poor contact thus resulting in cooling issues. If the surfaces are also scratched or dinged then that can cause issues as well. To fix the problem users will usually lap both the cooler and processor. For more details on this process check out this link: http://www.overclock.net/air-cooling...ltake-big.html.
Just FYI you do not have to spread the TIM across the IHS. The "die" is on the middle of the wafer so technically that is all that needs to be cooled. For your reference here is the application instructions straight from Arctic Silver: http://www.arcticsilver.com/ins_route_step2amdas5.html.
Remember pressure from mounting the cooler will evenly spread the TIM so don't worry about manually spreading it.
Hope that helps
EDIT: N2Gaming I have not lapped either yet and am using AS5... I also read some reviews and decided it should definitely be a good jump better than my ACfreezer64pro...... maybe I concluded wrong.
Edited by ny_driver - 1/11/10 at 6:41pm