Macintosh Multitasking Performance Sucks?

[Kent Borg]

I am thinking that Mac OS X doesn't multitask so well. 

My wife has a Macbook Pro 17", about two models back, 2 GB RAM, running 
Darwin Kernel Version 8.11.1 (one major rev before Leopard, whatever cat 
that is). 

I am running an rsync backup to an encrypted disk image on a USB disk.  
I have niced the rsync processes, limited the rsync bandwidth to 5000 
KBytes limit (which I suppose I am not hitting).  Currently the machine 
is also running Itunes, Mail, Firefox, X11 Openoffice, plus all the 
required stuff (Finder, Dashboard, etc.).

Problem: Interactive performance is *terrible*.

Running top, the idle is usually over 70%.

Questions:

  1) Am I trashing some key cache?  (How can I avoid that?  The rsync is 
running slowly enough as it is, but I can slow it down more...)

  2) Am I thrashing the disk?  (How do I read the mem usage in the 
Macintosh top? "wired"?, "active"?, "VM: 10.9G + 140M"?  What does that 
mean?, is it really running a current 11Gs of swap??  I am running far 
more stuff on Ubuntu right now and I am using only 1 GB of swap with 
only 1 GB of RAM.)

  3) This seems much worse than Linux, am I tricking myself?  Is 
BSD/Darwin doing something stupid here??


Thanks,

-kb, the Kent who is more and more impressed with his little Panasonic 
W4 sub-notebook every day.

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