Most of Apple's iApps are dogs.
Well, sure, Mac OS X itself is pretty much a dog (in its UI).  Mac OS runs circles around it in many respects.
But that doesn't excuse 600K of calendars taking up 40% of my RAM on a 512MB machine (according to Process Viewer) in iCal.
Nor does it excuse that it takes more than 30 seconds to start on a G4/667.  And about 30 seconds to move something from one (~300K) calendar to another.
iChat isn't very slow (how could it be?), but it is pretty buggy.  It crashes a lot.  iCal has some significant bugs too, though it's not crashed on me yet.
Which isn't anywhere near 600K.gnat 1206 0.0 6.5 193992 50780 ?? S 8:42PM 1:55.93/Applications/iCal.app/Contents/MacOS/iCal -psn_0_10878977 
You're just cursed.  Sucks to be you.  Rocks to be me, with football games, DVD releases, movie releases, and holidays all synched with iCal
--Nat
Re:Weird
pudge on 2002-09-11T22:12:30
How big are your calendar files on disk? ~/Library/Calendars/. Mine topped 600K. That's what I was talking about.
Re:memory usage
pudge on 2002-09-13T15:07:57
Are you sure that you are reading the Process Viewer output right?
When it says "% Memory" and below that reads "40", yeah, I think so.:-) 
Note that I have *only* seen this with a large-ish calendar. No one else I've talked to who reports significantly lower memory use has had a calendar.ics file larger than 300K, let alone 500K or more.