Name the culprit

[Dee-lish]

I'm having these intermittent hangs where
none of my apps are responsive for 5-10-15 minutes, then suddenly will "wake up" and the backlog of various keystrokes and menu selections will suddenly execute.

The behavior has the "feel" of insufficient RAM. Except I have 1.5 GB.
Typically I'll have Illustrator, Quark, Acrobat Pro, Word, FireFox, Entourage open.

Could I be hitting my RAM ceiling? Is there a way to get OSX to warn me when I have too many apps open? I thought this was an issue of the past, but maybe 1.5 isn't enough for the way I work...

I do have a few system hacks which could be the issue:

Butler
App Enhancer
MacAfee Virex

Also wonder if FireFox (2.0.0.10) might be the culprit, with its infamous RAM sucking issues;

I'm the only one in my department that uses FF, and I'm reading that several other people have the same symptoms: after a few hours of opening several pages/sites, I get the spinning ball of death, hangs of several minutes...

I've run the free utility FontNuke just to verify that font caching is not the issue...

 

[Mikuro]

Open Activity Monitor (in /Applications/Utilities), and sort the list by the "Real Memory" column. That'll show you if any application is going nuts with RAM. Firefox should use about 50-100MB.

I recommend leaving Activity Monitor running all the time, so that any time this happens you can quickly switch over and see what's using your RAM and CPU.