why is my desktop sluggish?

Sat May 11 20:59:49 UTC 2013

I'm using Gnome on Fedora 18.

I have a lot of windows and tabs.

Firefox is huge, lots of windows, but Resident Size is only 1.5GiB out of 
6 GiB that the hardware has.  Nothing else is near that.

Firefox is taking 50% of a core, but heck, I've got four cores.  Nothing 
else is near that.

I don't think that anything is eating disk or network bandwidth.

So why is my desktop window manager laggy?  Dragging a window or creating 
a new one isn't instant.

What should I be monitoring / measuring?
--
The Toronto Linux Users Group.      Meetings: http://gtalug.org/
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://gtalug.org/wiki/Mailing_lists