Difference beetween Penumbra original and Overture Episode 1

[denyboy]

When i was playing penumbra from downloaded from: http://frictionalgames.com/penumbra/

graphic looks phenomenal. Shading looks good. Game is dark, and flashlite look usable, FPS is good. Light effects are good.

But when i installed Overture Episode One.

Game is not so dark, FPS is lower, flashlite effects look very bad, glowstick effects look very bad, sometimes i have flashlite on and its all dark anyway, there is some ugly lighning as it is cubic. Some objects near me are almost 100% dark black. And Flashlite and glowstick effects are weird with lot near and far objects staying black. Some far objects turn suddenly from black to visible when i come closer.

I have Pentium 4 3.2 Ghz 512 RAM, ATI Mobility Radeon 9200

What could be problem. Penumbra look good, but Overture look bad. I could add screenshot if its needed.