I have had this problem and after hours and hours of searching the internet I got it by chance in a non related post. I am therefore posting this thread to help others.
The cause for this problem (If it is not hardware related) is that you have reinstalled windows (7). In your device manager you will see a yellow flag by pci controller thinking it is a modem you did not worry about it.
You need to install the "Turbo boost Intel" drivers. That installs a couple of things extra it seems but most importantly it installs the fan speed controller.
I installed these drivers: http://s000.tinyupload.com/?file_id=72519850719249139585 uploaded by someone else. I only installed the 1st driver pack as per readme file and this solved my problem. Doing a stress test with cpu's at 100% temperatures remained constant at 90.
I did re-paste after removing all the fluff out of the fan assembly and was to liberal with the past causing the higher temperatures. I would suggest to download the turbo boost intel drivers from acer but I was to tired of searching and this one in the link solved my problem.
Happy computing!
Acer travelmate 5742G Fan not speeding up, cpu overheating
Discussion in 'Acer' started by Jan van Coppenhagen, Dec 9, 2015.