I pull my heatsink once a month and clean it out.  I blow out the CPU fans every week, along with the 8 other fans I've installed.  This makes a big difference in performance.  Also, if you pull the heatsink, get some really good heatsink stuff ... my son works for Dell and he give me silicone jelly for my heatsink and says it's the only stuff to use.

Hugz from Phoenix, USA

Victoria

Remember, sometimes the dragon wins. Correction: MOST times.