Odd hangs with RT 3.0.9

I recently upgraded to RT 3.0.9 (RHEL 3, mod_fastcgi-2.4.2, perl
5.8.0, MySQL 4.0.13) and have been suffering from occasional hangs. Every
now and then, the perl process will peg the CPU for a minute or two. During
that time, other RT requests will time out. If I wait a couple of minutes,
the problem goes away. The error logs show no problems other than the
This doesn’t seem to resemble any of the performance problems I’ve
seen in the archives. The machine is weak (P3-500 w/256MB RAM), but it’s
not under any kind of real load. Most of the time it behaves just fine.
Any ideas what this might be?