That is a little warm. How much Arctic Silver did you use? You should use no more than the size of a grain of rice directly in the middle of the cpu. When you clamp on the HSF, it will spread out to the needed areas on it's own.
What kind of airflow do you have in your case? You should have intake on the front and exhaust on the back. Also clean up your cables, tie them up, stick them off to the side. Cables greatly obscure your airflow. You want air comming in the front, going over your components, and exiting the rear.