I ran the laptop for 5 hours yesterday without it blue screening. I don't know how much this is attributable to the cleaning of the heat sink. I think the greater help was the fan utility that I downloaded from a link on the site I mentioned yesterday. You can find it at http://www.diefer.de/i8kfan/.
When I first booted the computer the CPU was running at 53°C (about 127°F). I set up the utility to run the fan at low speed when the CPU hit a certain temperature. At this point the CPU's temperature dropped such that it peaked at 42°C (108°F). I noticed, though, that the hard drive temperature was slowly climbing, passing 41°C to 42°C in a half an hour. I set the utility to run the fan on high for the rest of the evening. This dropped the CPU temperature to an average of 37°C (98.6°F, or average body temperature) and the hard drive maxed out at 46°C (115°F). The CPU temperature climbed late in the evening when I installed the latest Windows updates, which were both CPU and hard drive intensive, but the CPU didn't go above 42°C and the hard drive stayed around 47°C.
This all happened with the Chill Mat turned off. Tonight I'm going to see what happens with the Chill Mat on. I will also experiment with setting the laptop's fan to turn on and off based on the CPU temperature, instead of running it full out all the time as I did last night.
It's ridiculous that I have to do this, but if will be worth it if it saves us having to buy a new laptop for the time being.
4 Good Years
9 months ago