Some of you may still have this proble. Basically, if you quickload a game from anywhere, the frames per second drop about 40-50 of what you normally experience. Quick solutions include going into binocular/thermal goggles, then going back out. This works only sometimes, and doesn't bring you back up to your full FPS. The only solution I've found is to create a new game, then load your game from there. Then I get normal franrates, around 60-110. If I quickload again, then the FPS drops to around 15-40.
I thought they'd fix this serious bug, I've even mailed Kenn Hoekstra about it, and he said he'll look into it. *sigh*...
You are absolutely correct, I have the same problem. That really pisses me off that they can't get that fixed. I guess they figure by now that people have already beaten the single player game so why fix it? Geez.