Server slows down and reboot is required. First problem is Webmail

I recently converted our server from a SUN running Solaris 9 to Dual G5 OSX 10.4. The machine will run for a few days until it slows terribly and then needs a reboot.

The services that are affected are Webmail/Squirrelmail, PHP, MySQL, and UNIX in general.

When I run a command like “time which ls” the response is about 4.5 seconds vice .004 seconds. PHP same issue time php script yields a 15x slower speed.

The server is configured with 2GB RAM, RAID 0 Dual drives, OS 10.4.11 (Fully patched). MySQL 5, PHP 5.

I have checked Performance Cache and it is disable for all virtual servers. We are using Cronolog for apache web rotation with the same configuration as in Solaris.

I suspect the issue is in the SPAM filtering via PERL. CLAM AV gave me too many issues and I had to turn it off. (No good directions for converting them to daemon mode).
It appears to be a memory leak of some kind however I am not seeing PAGE IN/OUT issues during the problem. What I see is 50% CPU time to sys. I have tried to turn off (MAIL, WEB, FTP services) and restart but that does not seem to affect the issue.

I have changed the apache configuration from 10,000 connections to 10 for child processes. I also do a graceful restart on apache every day. (using apachectl)

It is insane to reboot a Unix server every 5 days or so.