One isolated AFP thread uses around 5.0 MB of memory additionally to the operating system - Windows NT 4 uses around 30.0 MB. With 64 MB RAM your system might drive 5 to 6 AF threads without swapping to harddisks. On a machine with 256 MB there are approx. 40 parallel AFP threads possible but that's not really necessary. Less is more...
Note:
This article is only valid on version 2.4.6 or lower.