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I believe I can take the cake on this thread.
I have been running my iBook 500 with 64 MB of RAM for almost a month now!
Hopefully my 256MB chip will come soon...

I tried to use OS 9 instead, but I couldn't stand it for any amount of time.
So, OS X with 64MB is a fun time. It takes a little bit to load some programs, but I still use it every day.

I STILL LOVE OS X!
 
Download Memory Usage Getter. It will tell you how much memory is being used and whether you are getting Page Outs. Then you 'll know whether what you do requires more memory.
 
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