I’ve been having problems with Adobe Reader eating up all the available memory and taking tons of cpu cycles. I really would rather use an open source program like KPDF, but printing from it is broken and they have no intention of fixing it according to something I read on their mailing list or on a bug report somewhere. So for now I’m stuck with Adobe.
Edit->Preferences->Internet-> Allow fast web view & Allow speculative downloading in the background
I tried the fix and am now witing to see if the problem occurs again.
Update: The fix seems to work, but for some reason my settings were reset to being checked and the problem cames back. If the problem starts occuring again double check the settings and make sure they are unchecked.