Performance problems after combat?

[MercenaryForHire]

I know that combat isn't the central focus of Penumbra, but cutting performance after entering it doesn't seem to be the right way to do things.

See the attached screenshot. I was getting 4 FPS in that. Before attacking the dog, I was getting around 16 in the same spot. During the combat, I was getting one. I only managed to kill the thing by memory.

The big three specs here are: Mobile Celeron 2.13GHz, 1GB RAM, 6600GT. I know it's not a scorcher of a system, but look at the screenshot. Everything is on the lowest possible detail, and it's still getting single-digit framerates.

Forceware drivers are the latest - 93.71 - and performance in other games is fine given the age of the system.

What gives?