I'm getting floating frame-rate on one of my projects I've been working on. The FPS in unlimited frame-rate mode would be around 80fps at start and after some time it will drop down to around 30fps and get back at 80fps after some period of time.
The 80fps as max unlimited frame-rate is also worrying but I can get past it. (My machine runs at 3.0GHz with 2GB RAM, so I guess it's powerful enough to run at higher frame-rate than that.)
I have found that removing positional audio and two groups of events improve frame-rate a bit (goes up to 100fps), but frame-rate was still floating. Removing particles didn't make any change and I make no use of effects.
CAP-only ZIP (80KB):
(when frame-rate drops? Do the following - go to the left, pick-up the gun located at top of the building, go to the right, keep going to the right and the frame-rate will drop at some point)