Sony :: SZ6/7 Overclocking 8400 GS 64MB

I asked around and people said that the 8xx Series nVidia GPU is defective and its very high risk of bricking my PC if i do so, others have said that its possible but to a small boost which is more than fine for me, becuase when im playing games or whatnot, then my screen freezes for a second.like if im playing a racing game and i have the up arrow key pressed and turning right and have them both held the game freezes untili let go of both keys and it returns like it was just frame hiccup or something nothing major but its a bit bothersome.

It still irriates me ALOT that even though Sony moved up from 7400 GPU to 8400 GS then DOWNGRADED the video ram from 128mb to 64mb which really sucks. I just sold my SZ4 for a pitiful £250 and bought an SZ60WN/C off my uncle for 350, but I feel like the overall performance of the SZ4 surpasses the SZ6 I notice a good amount of slowness...im not gonna say lag but slowness in the things i do on normal bases whether its multiple tabs or photoshop or anything else.

Now I know OVERALL the 8xx cards are defective but I heard that only some models were defective does this affect the SZ6/7? and anything I can do to OC the GPU or speed up my system by anyway.

MY ram is PC-6400 667 bus speed would i get a good speed bump moving upto a 800Bus speed RAM?