PCI - Express ??

[celik]

My computer is a good system which runs any recent game with max settings and resolution with great fps. Some examples include BIOSHOCK - The Rapture and CRYSIS. But Penumbra is unplayable !

3.2 Ghz P4 Genuine / 3GB Dual Ram
PCI-Express Chipset
Geforce 8500 GTS 512Mb
XP Professional Ed. SP2

My friend brought me this game, after finishing it. He says it works fine in his computer which is worse than my computer but in my system, framerate drops to lower than 1 fps during any action and sometimes at other times. Worst part is, it's getting worse: about 7-8 seconds/frame

Hell I don't even know how I even made it to here. The game is fun enough I guess.. but it's impossible to go on further.

I have the latest drivers for everything and updated the game with all possible patches (tried all the intermediary steps as well). I even ran it with NO other programs or residents running: Nothing.
(Which is useless, Because I know my system can run half a dozen games simultaneously)

And nope it doesn't work at all..

Funny part is the performance is exactly the same for ALL settings. I tried the absolute minimum settings for everything and the only difference was the game looked very bad as well.. So I decided to max out everything.

One question: Can this be because of the PCI-E chipset I have?