It's not as good as it should be. Does it get hotter when you play a game?
Arctic Silver 5 says on their webpage that you need to turn off the PC and let it cool down several times before it gets to the final temp.
Did you follow their guidelines? They tell you what shape drop to use and how to clean and prepare the surfaces. I thought the tip to use coffee filters as clean cloths was clever.
Is there a heatsink on the graphic chip?