fx5200go overheat(?) problem

[treks]

i own a mobile geforce fx 5200 go gpu on my notebook

when i run some graphics-intensive game (like doom3 or farcry) just after i started my computer after couple of hours of standby, i get a descent gameplay (50-60fps) for about two minutes maximum.
then framerate drops to 15-20 or even 7-8. restarting the game and/or computer didn't give any results, framerate stays low.

only if i turn off the computer and let it "cool down" for couple of hours, i then get 50-60 fps again but for only one or two minutes. then the fps drops down again.

640x480, lowquality
i get about 20fps +-5 at main menu in doom3.

notes:
(pentium M 1.3ghz, 1gb ram, 40gb hdd)
installed 61.77 detonator driver
'powermizer' set to 'maximum performance'

i think gpu thinks its too hot and drops speed.
is there a way to turn off this 'feature' or some other workaround?

thanx

[Zeta]

I wish I knew the name of it but there is a stand you can get for laptops that have fans and lift the laptop off the table to keep them cool. I have a friend with an alienware laptop and he has the exact same problem with doom 3 right now. When he plays doom 3 it gets so hot it just quits the game unless he runs 640x480 with everything on the lowest.

[treks]

dont think my laptop is that hot
and fan hole is at the back so no problem with hot air heating laptop again..

doom or anything doesnt quit. it keeps running just too slow