Over the past year I have noticed that my cpu temps were getting a few degrees C higher than I remembered from when I first built this unit. I thought that maybe it might have something to do with the ASII's "aging" a bit. I had used canned air before to blow out the fins on the HS so I "knew" they weren't dirty. I had the case open the other day to install a new CDRW and decided to take a closer look at things. At first I was going to pull the entire unit and reapply the paste. Then I decided to pull the fan and have a look first. Wow, was I in for a suprise! There was a "coating" of dust on tip of the HS fins, blocking the airflow from the fan by about 20% at least. It appeared as though the dust started collecting on the tops of the fins and then just grew, like a spider web. Possibly this is because of the closeness of the fins, I'm not sure. In any event, if you are noticing a few extra degrees of heat you might want to take a look at this. BTW, I have since installed some filter media on my two intake fans to hopefully keep this from happening again. Just thought I would pass this along. I have "regained" ~ 6 degrees C because of this Spring Cleaning. 😀