I first noticed this a few days ago when testing on Firefox, but put it down to the FF GC which people have mentioned. I did some optimising anyway even though it was running smoothly at 60fps in Chrome. In particular I removed about 500 objects, but those were on seperate screens anyway and that didn't change anything.
Since then, I've put more objects in my game and I'm now up to around 1300 objects in total. The majority of these are still on the seperate screens - information screens which run at 60fps and don't require decent fps anyway because they're static. But now my game is starting to stutter on Chrome too (on the arcade screen which only has about 200 objects showing at most) and runs around 55 to 59 fps. The stutter appears to be exactly once per second.
I've tried testing my latest code additions and disabling them, but it still stutters. The slowest of them takes 0.004 seconds to process but I've set that to process only once per 10 seconds, so it can't be that. I did think that my optimising might be causing this, because I set loads of calculations and other stuff to process once per second, so there's no calculations them BAM, everything calculates on the same pass. But I've changed these to 1.2 seconds, 1.3 seconds or more, to try to get them to process at different times. Still no difference.
I've also tried disabling each group one by one, but nothing is making a difference. I did disable almost every group and it started to run smoothly again but obviously I can't delete 75% of my game.
Is there anything else that could be causing this sort of stuttering? Could those 1000 off-screen objects be a problem, even though they're on invisible layers? Is there anything else internal to C2 that might cause this sort of thing?
I'm afraid I can't supply a capx because my game is over half done and I really don't want to show it yet.