In ‘We’ve Got Hostiles’, after getting to the surface (badass music starts :jizz 
, when I save and load the game from there, I get as low as 20-30 fps, then after a few seconds it gets back to 40-60.
The real problem though is the mortar firing, when it hits the ground the fps tanks to even high 10s. Also I noticed similar problems in the ‘Blast Pit’ in the tentacle chamber, and in ‘Power Up’, although not gamebraking.
I hope this can get fixed, and am aware that many people are reporting similar issiues.
Even with all these problems this mod is BEAST like OVER 9000 GARGANTUAS!
My specs:
C2D E7200@3.4 GHz
4Gigs DDR3 1333 RAM
Gainward HD4850 GS
Windows 7 x64
Edit: Oh and, yeah the game runs great otherwise, all high with 2xAA, 4xAF in 1440x900 res.