I have not had this happen often before, but recently I was simply playing a video project (VEG file, using an MXF file in 1920x1080 format). The audio cut out for several seconds, came back, cut out again, repeatedly.
I lowered the preview to Draft quality; while the display was affected, I still had the audio dropouts.
I checked that my antivirus program was not doing a full-disk scan -- and it was not.
I'm playing back from a local drive on a very new Dell quad core with 3 GB of RAM.
Suggestions?