In 4.0.1, I am running the Raiders2 or any other clip from the demo composition. All other layers are empty.
When the Transport bar is open in the Clip properties, FPS drops to 34 fps or so, but when I close the Transport bar, fps jumps back up to 60 fps!
When a clip is running on Timeline mode, the fps is about 34, but when I change it to BPM sync, fps jumps up to about 52 fps, returning to 60 when the Transport bar is closed.
Playing a clip on each of the 3 layers in default composition, fps is about 29 with the Transport bar of ALL clips closed, but as soon as Transport bar is open for one or more clips, it drops to about 21 fps.
This is 100% reproducible in the current session.
XP Pro SP3.
Win7 x64 Pro | 8GB | Nvidia Go 650M/2GB