Daniel,
CentOS 3.3 on a Pentium II with 300 Mhz, a Pentium I
with 166 Mhz, one K6 system with 200 Mhz, all
working
fine, working as little build farm and test suite
for
development. All systems have at 64MB RAM installed.
I had yum problems on Pentium I's with 72 megs of memory -- yum would crash a lot. (This was running cAos 1, not CentOS.)
I am surprised that 64 megs is working well for you.
Rick