MacOS X and its predecessor NEXTSTEP share very similar performance characteristics when the amount of memory is not adequate: they system thrashes and becomes more and more unusable. Switching between apps takes a long time and the computer cannot keep up at all. While moving the swap file can and does help a little, this is just a band-aid to the real problem: a lack of memory. Tricks like moving a swap file are fine for server type applications. On a user environment a few dollars can make a bigger difference.

The real fix is really to add more memory. Lets face it for $89 you can buy a 512MB DIMM and even low entry iMacs can now take one full GB. Seems to me that best investment one could make includes maxing out the memory on the machine as much as you can afford. A 512MB or 1GB machine will be a very different animal. The swap drive under normal conditions will not really be used and things will run very differently (and fast).

What does a 1GB Mac OS X feel like? They way it should.