> How about a PIII-500 machine with 384 MB RAM running from an 1GB USB
> stick?
Machines with much smaller memory and slower processor were used as
departmental mail servers not that long ago. Believe me, it's a no
brainer. I run postfix on my Neo Freerunner (128MB RAM) and haven't
noticed it being a problem. If you don't use it, the kernel will swap
it out.
Stefan