cpu fan rpm slowly gets higher and higher

This has been happening for around 3 days. When I start the computer (desktop) up, the rpm is normal but it slowly starts to speed up. After around 5 minutes, the fan starts moving at a average of 4000rpm and it's really starting to worry me.
I thought it might have been something to do with dust inside the heatsink so I cleaned the dust with a vaccum cleaner. After that, it still wouldn't slow down so I changed the thermal paste. It now slows down a bit but still run at the average of 4000rpm.
I also tweaked with the bios a bit but still no luck.
Help?

Have you checked actual temperatures to see if there's a corresponding rise with increased fan rpm? Couple of free utilities:

Speccy - System Information - Free Download

SpeedFan - Access temperature sensor in your computer

HWMonitor - CPUID - System & hardware benchmark, monitoring, reporting

yes, I have. And there seems to be a corresponding rise with the fan rpm.

jian57 said:

yes, I have. And there seems to be a corresponding rise with the fan rpm.

If your fan speed is increasing with a corresponding increase in CPU temp, that is normal and good.
The "system" is trying to keep the CPU temp down so it won't overheat.

If you have cleaned everything, and made sure ALL FANS are working OK, check Task Manager to see if you have something running that is using a lot of CPU.

Start Task Manager (Right click on the taskbar)
- click the "Show processes from all users"
- click the "CPU" heading so the highest numbers are sorted to the top of the list

Post a screen print of what you see when the fan is running fast.
Screenshots and Files - Upload and Post in Seven Forums

Here is an example showing 92% CPU usage for "System Idle Process".

windude99 said:

When was the last time you cleaned your computer with compressed air?

I cleaned it just a few days ago.

DavidW7ncus said:

jian57 said:

yes, I have. And there seems to be a corresponding rise with the fan rpm.

If your fan speed is increasing with a corresponding increase in CPU temp, that is normal and good.
The "system" is trying to keep the CPU temp down so it won't overheat.

If you have cleaned everything, and made sure ALL FANS are working OK, check Task Manager to see if you have something running that is using a lot of CPU.

Start Task Manager (Right click on the taskbar)
- click the "Show processes from all users"
- click the "CPU" heading so the highest numbers are sorted to the top of the list

Post a screen print of what you see when the fan is running fast.
Screenshots and Files - Upload and Post in Seven Forums

Here is an example showing 92% CPU usage for "System Idle Process".

Here is the screenshot:


And I will fill in my specs later.

88% CPU usage for System Idle process should not be a problem that would cause overheating.
If you keep Task Manager open, does the fan speed and CPU temp decrease?
There is some malware that hides itself when Task Manager is opened so the user doesn't see it, and CPU usage looks OK...

No, the fan doesn't decrease. It runs normally.