It seems as though MacOSX 10.4 is a wee bit memory hungry... My Powerbook has a gig of RAM, and I've been stuck in VM thrash hell for several minutes on a couple of occasions (which hadn't happened at all since I upgraded to 1GB from 256MB while running 10.3). I don't recall exact memory usage on 10.3, but Safari alone is filling up almost 200MB of real memory, with almost half a gig of VM. 4 instances of the Weather dashboard widget suck up almost 90MB of real memory each, totalling a whopping 1GB of VM.
I'm hoping I'm misreading this, or if it is a real issue, that it will be resolved in an update somehow...
![Tiger memory usage](http://www.darcynorman.net/images/memory.png)