If your game is complex, rendering might not be the only problem. Anything involving intensive loops will heavily impact performance. The events that you should be particularly careful with are ones which are computationally expensive, and are called every frame. For example, a loop that iterates through 500 sprites every frame, and then checks collisions with each one against 4 objects. You should absolutely try and optimize events like these, because "1" simple expensive event like that might cut your fps in half if left unoptimized. It's not the number of events that matters, it's those which are expensive, and those which are called every frame.
"Things working great" is entirely platform specific, so those 1000 events you removed might not have an impact on a fast machine, but you'll notice a difference on slow hardware.
You see, each machine has a critical point where your events (or game engine: i.e having too many objects existing at once) start using too much cpu time, and it drops below 60 fps. Any optimizations made when above this point are unnoticeable, because 60 fps is the same as 100 fps, or even 1000. Your screen only runs at 60 fps (most do), so anything faster is not noticeable, in practical terms. But once you drop under 60, the game is "lagging", and isn't running at full speed. If you develop on a fast machine, the critical point may be so high that you're unable to see any poor performance, even if your code is horrendous. Switch to a slower machine and you might see a difference.Davioware2012-09-15 23:30:09