[mythtv-users] Delays in navigating Guide

[Norm]

I've recently upgraded from a P-4 3ghz to an AMD Athlon(tm) 64 X2 Dual
Core Processor 5000+ with 2Gb of RAM.  Using an on-board Nvidia
7050PV/nForce 630a video card.

I installed Mythbuntu 8.04 32-bit edition.  (I did try the 64-bit but
wanted the extra windows codecs).  

Runs great watching live TV HD or otherwise via firewire.  The problem
is the guide.  When I jump to the guide, I can't seem to easily navigate
it without it freezing momentarily.
I've added the mysql optimizations from the wiki.
I run daily the purge script to clean up old guide data.
I weekly run the optimize_database scripts so I don't know why it does
this.  

CPU is not burdened watching live TV. Has anyone seen something similar?
Any suggestions are welcome!

Norm