3D graph.manipulation slows my computer until turn off & on again(reboot doesnt work)
 

I've got a really annoying problem and I would need some help.

I've got Fedora Core 2 running on a laptop P4 with an Intel 845GV chipset compatible with VGA UMA. I have used linux on this laptop since December, but now that I need to use mathematical 3D graphics manipulation (with Matlab and other software) I find that, after some time of manipulation, the computer slows down considerably. If I try, for example, to move any Nautilus window (without any other program running), the frame moves very slowly and after the cursor. When I reboot the computer, the memory test at boot goes much much slower than usual. For restoring to the "normal" speed, I have to shut down the computer and start again.

Please, I would be really interested in any suggestion.
Thanks.

You know, it almost sounds like an over-heating problem. I was about to ask regarding output from top, but mem would be cleared on a warm reboot. Is there any way for you to check the temp?

I already don't know if I can check the temperature. I will try the laptop in a colder atmosphere to see if there still persists the problem, but I have discovered that I can return to the "normal" speed (like when sutting down and booting again) by rebooting and, when it does the memory test, accesing the bios and automatically exiting saving changes.

Do you still think that it can be a problem of the refrigeration?