Frequent System Restarts

Hello,
I'm developing with SF5.0 (upgraded from SF 4.x).
The system keeps restarting every time i refresh the page to check or debug.
When i change some of the master pages or custom constrols it restarts (which i guess i can understand but SF4.x didnt restart on the same kind of changes).
But the strangest thing is that after it restarts, if i refresh again (no changes this time) it restarts again and it does this for about 3-4 times on each postback.

I can't attach the code, but i was wondering what are the reason Sitefinity "chooses" to restart the system (no web.config changes)? and how to avoid this?

Thanks,
Lev Rosenblit

Perhaps the AppPool is gets to its max memory limit then reboots itself?

Probably not.
On the production server (IIS7) its fine, only on casini it restarts a few times and then stops and works fine.