I have several Macs, and with the recent 10.3.3 update I did the normal -- download it once off the slow net, and then copy it around to my Macs on the fast LAN.
Well, while I was running it on one machine (an 800Mhz iMac G4 15" w/768MB RAM), I was wondering why the "optimization" step always takes so long at the end. You know, it runs fast up till about 80% then slows way down. So I opened Terminal and ran top. I had a bunch of regular things show up, most using very little or no CPU time. But there were two things using the bulk of the CPU time, the "Installer" and the "Update Prebinding" (the optimizer). What was amazing was that the Installer was taking almost 50% of my CPU time! Leaving the real work that Update Prebinding was doing with about 40%, and the rest for all the other misc tasks.
Minimizing or hiding the Installer window drops its CPU usage to less than 1% and the Prebinding then gets about 80% of the CPU or so -- quite a difference! I am guessing the animated progress bar is sucking a lot of juice. My subsequent updates went much quicker than usual with the Installer hidden. All of my machines, however, are single processor. This might not have much impact on a dual processor machine, and of course all of you lucky G5 owners might be saying - "What needs speeding up again?"
[robg adds: A previous hint discusses quitting the Finder to improve prebinding speed, but this hint seems much more likely to have a direct impact on the process.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040316010718477