One last observation on the problem:

Top says cvs is in biowait almost all of the time its running. the other jobs
jump around from RUN to select, to occasional biowait for the mailer (it scans
the MH mail directory tree a *lot* when you do .procmail based delivery and
then ask it to 'check folders'). but cvs is essentially always in biowait,
when its not in RUN state.

The free total is hovering around the 700k-3000k mark, although nothing like
that much memory is really consumed by user programs. I think the vm tuning
has consumed it all for file I/O buffering judging by:

Memory: 122M Act, 62M Inact, 564K Wired, 30M Exec, 99M File, 2560K Free

and

10 root      18    0     0K   54M syncer     0:04  1.56%  1.56% [ioflush]