RHELv4 and v5 - So slow as to be unusable.

[Gary E Barnes]

The past week I upgraded our RHELv3 machines to v4.  Previously we had 
several v3's, one v4, and one v5.  The v5 has never worked.  Now the new 
v4's are acting up.

Boot the machine, things are fine.  Wait overnight and the machine may 
take ten minutes to unlock the screen, may take several 10's of seconds to 
do an ls, and generally simply isn't usable.

The v4's if you reboot them seem to be fine for the day.
The v5 if you reboot it is fine for maybe 15 minutes.

The v4's, there will be a load average of 3 to 4, but top says nothing 
whatsoever (other than top and the xterm) is running.
The v5, there will be a load average of 0.1 or less and top again says 
nothing is running.

SELinux is turned off.  Firewall is turned off.  I've even tried turning 
off every service that isn't vital to being able to simply boot the 
machines.

Any ideas?

        Gary