RandomOne,

Its good you didnt have any heating probs so far, but cleaning the heatsink with compressed air is a good way to prevent the dust caking on the fan....

My Inspiron 5100 developed a heating problem after six months. It was returned Dell for repairs and the documents showing worked performed included cleaning  the heatsink. My laptop is working properly now but I use compressed air about every two weeks.

If I knew that the dust was the potential culprit for overheating, I would have taking the preventative measures from the start. 

This is for Randomone.

Even if you keep your 5100 machine at 100% cpu usage for an hour straight, you shouldn't really go over 61ish.  So you say that you are idling at around 40 something, which is a bit high, but still good.  But if you get up to 65C while doing video editing, then you already have dust on your heatsink.  If you spray it out as explained in the post on the top of the forum, your temps should drop a few degrees.  But anytime you get over 60ish while at 100% cpu usage for some time, you konw it's time to respray the air.

cazint.

okay guys.  this has been talked about too much.

if you want to clean your heatsink.  do so.  if not.  don't do so.

1.  Some people don't start have problems till 5 or 6 months.  I started at around 4 months.  Others might take a year.  It obviously depends on several factors, namely the amount of dust in your environment, and the amount of use on the computer.  If you are in a dusty area, and your computer is on 24/7 (i.e. always bringing in the dust via the fan), then it will be quicker.  So it depends.

2.  if you have a 5100 with a pentium 4 processor, the MAXIMUM temperature that your case can get is 74C!  After this, it WILL shut down.  Period.  This is not my words, but that of Intel:
http://support.intel.com/support/processors/pentium4/sb/cs-007999.htm.  So whatever FANgui says for the specs for fan speed slow vs. high, that is the choice of fangui, which is a third party program.  So the fact only that fangui has "two more regions of 70-80C and 80-85C" is not an evidence that the processor can go up that high.  Because, the bottom line is, that according to Intel, the max case temp. for the P4 2.66 MHz is 74.

also, from what i am aware, there have been no design changes thus far.  I can be wrong.  But I believe this is nothing yet, not even for the newer ones.  However, dell is working on the problem.

So as i said, your idle temp seems okayish, but is a but high, but only a few degrees.  Therefore, okay.  But once you start getting over 61 or 62, you know you are getting caked dust, and to beware.  That is all.

cazint.