Logic live outputs pops intermittently?

Question

Using Logic Pro in a live setting in church concerts, I'm getting random pops in my main FOH output, and I cannot pinpoint the reason, unless I am just taxing my laptop's capacity. Anyone else with experience on a G4 over-taxing the CPU and getting pops or clicks?
Here's the problem:
Maybe half a dozen times during the 2 hour concert, I will hear a minor pop in the FOH output, usually during music. Sometimes it happens just after I slightly change the EQ on the main output, sometimes it happens when I haven't touched the computer for 30 seconds or so. It appears to be almost random.
Here's my setup:
Using Logic with iBook G4 (1GB RAM) and MOTU Ultralite Firewire audio mixer doing live, single mic gospel concerts. Using iTunes to playback .aif stereo tracks, and using Shure wireless mic and wireless IEM monitors. Pretty simple setup, 1 mic, 1 stereo feed from iTunes (going out to MOTU Output 7-8, then analog patch cords to MOTU Input 7-8). Two stereo outputs, FOH and IEM. Using Aux objects as inputs, buses to get to SpaceDesigner reverb and IEM output mix. Doing some EQing on mic, IEM and FOH output, plus compression on mic. Using 128 cache to keep latency unnoticeable.
Using the System Performance window, it is using just over 1/2 of the CPU capacity. If I turn Space Designer off, I am using an 1/8 of the CPU. I am not recording, nor moving the timeline at all. I use iTunes instead of laying the tracks end to end in the Arrange window so that I can freely choose between over 50 songs at the whim of the singer. And, it sounds great, and easier to carry than the 01V I was flying with.
Of course, I have no other apps running other than iTunes and Logic Pro and Stickies. But, the CPU capacity monitor being over 1/2 makes me nervous.
Based on the answers to this query, I am considering getting a MacBook Pro for the increased CPU, as well as bigger screen. But, if it doesn't solve the pops, I will have spent $3,000 for naught.
Thanks in advance for any help you can offer.
Rod-mixing live on a trackpad

Answer 1

Here's the problem:
Maybe half a dozen times during the 2 hour concert, I
will hear a minor pop in the FOH output, usually
during music. Sometimes it happens just after I
slightly change the EQ on the main output, sometimes
it happens when I haven't touched the computer for 30
seconds or so. It appears to be almost random.
Couple of questions....
Do you get the pops with Space Designer off?
SD has to process a lot of info and traditionally, laptops
don't have as efficient a bus system. If not using Space Designer clears up your problem then you pretty much know that the ibook's bus system just can't handle it.
But first!! try another player than ITunes. ITunes is not the most efficient file player around.
Also, if you do have to use another reverb, try using a couple of Logic's verbs, say a Platinum and a Gold. Sometimes using two lesser quality reverbs at lower settings can produce wonderful results.
paNceNter