Well, trying out this build was my first attempt to run Environment Mapping on my system. As I run without shinemaps to lessen system drain, I just used the standard version, and not the alpha-maps. I found that with -env on, gameplay tended to fluctuate in speed. Now there was no reflection (pun not intended) of this in the fps, but I noticed a definite tendancy for the game to accellerate and decelerate... but not in a stuttery or jumpy way. I was using pcx2dds by the way.
One other thing that may be an isolated incident. I found that once during mission loading, the timebar lights went out. When I got into the command briefing section, the CB ani were not present... not even the default ones. I exited the mission and restarted it, and still no timebar. I quit the game and haven't tried it since.
Later!