HP/Compaq :: Nc8430, Gpu Problems, Downclocking

Lately (last two weeks) my gpu has been dowclocking itself, that wouldnt be problem if it wasnt happening ingames (wow, wc3, hl2), even with powerplay off gpu still downcloacks itself to 392/250 from 425/380 and funny thing is, gpu alone swaps between those modes arounde once per minute. also when i alt+tab gpu clocks itself back to 425/380 (all this is happening while ingame)

now that isnt problem in wc3, but in hl2 and wow couses low fps (3-4 )instead of regular 40+ making games unplayable

i am using windows 7 x64, with all the leatest updates, didnt test if this happens on xp but willing to try, problem is i lost my recovery cd-s :S

Week b4 this started to happen i used mobility driver moder and instaled catalyst 9.3, noticed significal fps boost in wow and hl-2, even tryed fresh win instal with vista64 drivers for gpu from hp page (very old drivers) still it didnt solve my problem, mbo has latest bios availible from hp.

Some help would be awsome as i'm rly out of options and what to do, and rly dont feel like reinstaling windows once again ...

could i somehow disable powerplay or owerride it with ati tray tools? problem is i cant run any 3d aplication if att is on they just dont wanna start.