I recently had to replace my aging silent (fan rarely came on) Compaq Armada E500 P3 600mhz laptop with something with a little bit more power and in a lot better physical condition.

I got a very good deal on an Aspire 3100 Sempron 3500, 512MB RAM, 80G Hitachi HD, and 15.4â€

Have you tried undervolting as well? The 1.6 GHz Turion 64 ML-30 that came in my Acer Aspire AS5002WLMi is stable at 0.825V at 800MHz and 0.975V 1.6 GHz, and other people have gotten them even lower... CrystalCPUID can provide much better speed control than Windows.

I know it's still under warranty, but on another note, when I took my laptop apart, there was barely any thermal paste on the die itself, covering maybe half of the die area. Adding more significantly improved cooling performance.

The laptop has AMD Cool n Quiet technology install so for most of what I am doing the CPU is at 0.9V and 800mhz. I installed CrystalCPUI but I guess I don't have it configured right or its not compatible with this CPU, it reports the voltages and speeds and allows you to change them but I haven't noticed any changes in performance, maybe Cool n Quiet needs to be disabled.

Anyway I got brave again and open up the laptop and removed one of the thin pieces of plastic that covers the ventilation grills, the only use seems to be either to keep out dust (which I can blow out if needed) or to stop foreign objects sticking in, I'm not worried about that possibility the gaps are only about 2mm.

Removing this piece of plastic increased the area the exhaust air can escape from from about 1 sq inch to 3, for the same fan speed this dropped the cpu temperature another 5 degrees. To keep the CPU at the 40-43 range I normal run at (the noisy built in fan cuts in at 50 and out at 40) I can now run the external 12v fan at just under 6V, its barely audible.

Speedfan is now set up to sound an alarm at 46C and shut down the computer at 58C using an executable. The low temperature for the alarm gives me time to speed up the fan before the noisy internal fan starts.