Logic Pro 8 static and popping sounds in logic and other aps


At the moment my computer seems to be generating little staticy or popping sounds about half the time an action is taken. This can happen when opening an application, when opening a web site, and today it happened when I was writing automation in Logic Pro 8. I was using the latch mode to write in morph automation on an FM8 track. Almost every time the automation crossed one of those little white lines on the morph grid I'd get the static sound. I tried just moving the morphy ball around manually with the same result. This is the only track I currently have in this project so it's not a cpu issue. I'm running Logic 8 on a 24", 2.8 iMac with 4 gigs of ram. OS 10.5.6 and all software is currently up to date. Sound card is an Edirol FA-66.