Choppy mouse / video on laptop

[Duane Morin]

I'm hoping that maybe somebody can give me a lesson in how to read a 
system's load, be it memory, CPU, swap or otherwise.  I've got a 128M 
laptop running Mandrake and GNOME that's been doing just fine for me until 
lately.  Now it's become near unusable in its choppiness.  For instance, 
if I try to drag the mouse from one side of the screen to the other, I 
expect it to stop on me at least once or twice.  Not long enough that I 
could see a hard drive light go on, but just enough to be really 
annoying.  If I right click 
on something I'll wait 5+ seconds before the popup menu draws itself.

I'm doing Java development and running Tomcat often, which I'm sure is a 
real pig.  But even when I turn Tomcat off, it doesnt get much better.  
The only real apps I'm running are an Emacs window, a couple of terminals, 
and Galeon.  

It feels like the machine is constantly writing to disk.  'top' tells me 
that I'm using about 80M out of 256M.  Memory usage ranges, sometimes 
going as high as 120M out of 128M.  The thing that I don't know how to 
read is under CPU state, where it says 55% System.  Is that bad?  The load 
average is in the 5.x range.

[As a baseline, I just rebooted the machine and opened a terminal.  I 
still get 122M/128M memory used, now it's 1M/256M swap, and although 
system CPU briefly touched 50%, it now sits at 0.9%.  When running 
earlier, the system sat between 43-55% constantly. Load fell to 0.07, 
0.32, 0.17.]

Can somebody give me some tips about where to look for culprits?  If I 
think that it is spending a huge amount of time swapping, can I measure 
that and compare it against what it should be doing?  

Thanks!

Duane