First off, let me say that since I'm new here, I hope it's okay that I post a thread. I know some forums are a little touchy when it comes to this.

I have a Presario SR1215CL desktop with no special mods or over clocking. It's been a very reliable machine for my family, and I like to think I take very good care of it, cleaning both the OS as well as physically cleaning the heatsink and fan.

Recently (for about two weeks) the CPU fan runs at what sounds like max speed almost constantly. Immediately I searched for all the information I could grab regarding this issue and have found a wealth of knowledge, however it seems simply cleaning the machine has fixed the problem in every case I've read. Such is not the same for me, unfortunately.

I installed CPUCooL Version 8.0 on my machine to monitor my fan and CPU temps. Murphy's Law of course: As I post this, my CPU is at 49.5C with only 11% CPU usage. No fan. UPDATE: I opened a few programs such as Outlook, and two tabs on Mozilla Firefox, and I have a constant fan: CPU temp 70.5C TEMP sensor 75.5C CPU usage 96% and lagging. This sounds to me like I'm stating the obvious (of course if I"m running my CPU hard, the fan will come on.). Realize please, that I've had this computer for 3 years now and almost never heard the fan like I do now. I can't think of any new conditions that could be causing this problem, and I don't want to ignore it, as it may be a sign of a larger problem.
Most days I've been coming home to the computer sitting completely idle with no programs open, and the fan running constant. The fan will turn off, and if I so much as scroll down on Notebook, it will come back on.
To reiterate, the board is emmaculate, and the vents are not obstructed in any way. Am I missing something? Could there be a virus running in the background McAfee isn't catching? If so, wouldn't I be able to detect something wrong by monitoring my CPU usage when Idle (10% and below when idle, but fan is still on)?

Thanks in advance for listening to my concerns, and I hope I've been descriptive enough so that you may be able to help me. Oh one more thing. I have checked for BIOS updates and I'm current.
This site looks like it holds alot of great information, and I"m going to continue to browse. So glad I found this site!

To add, I just noticed that on the most recent instance, my CPU was at 59.5C but the TEMP sensor was 75.5C. The CPU usage was only 9% and fan was on.

Is it normal to see such a great variance between the thermal sensor temp and actual CPU temp?

Heya otisfirefly

welcome at GSFs. It's nice you found us at the web Hope you'll enjoy our community like many others before.

I know about such problems you're telling us. Fans can turn into a real noise-maker when they'd picked up some dust through the ball bearings of the fan. You can take care of the fans like you want, you can keep the inner section of your computer clean, but believe me dust will find its way.

On the other hand a malfuntion of the thermo sensors might be a reason for that problem too. When running a computer under hot conditions (f.e. like a hot summer) sensors get a glitch often.

Right now I can give you only one advice. Try to change the CPU heat sinker. Look out for a fan that is 2/3 larger than that one which is already mounted. It's does not produce much more noises as smaller ones but it does move more air to the CPU due to the larger size.
When buying a new heat sinker look out for hermetic encapsulation of the ball bearings and a cooling element made of copper which does transport the heat much better.

If you need more info or help... we're there ;)

Greetz
B. Udo


PS: Good luck when you're removing the old cooler and be careful, kay?

Thanks very much for the info and sorry for the late reply. I'll do as you suggest.
The only thing that I'm still curious about is the actual CPU temps. Doesn't seem to be staying at a dangerous temp, and if I"m wrong please correct me.
I suppose poor heat dissipation from a poor performing heat sink would cause my fan to stay running alot more often to maintain a safe CPU temp. Makes sense.
I'll be very happy if the heat sink corrects the issue, and will post results soon.
Thanks again.