Audio dropouts during file operations

Hi again, need a little help with a problem, audio playback using Foobar2000 is skipping at times when I'm moving files around my system. It doesn't matter which drives the files are on, it happens even when involving drives with no music files. I've tried upping the thread priority and increasing the playback buffer (in Foobar) to no avail. My board is an Asus P8Z77-V, and I'm using the optical SPDIF out from the on board Realtek ALC892. The problem doesn't affect video playback/audio at all. Any help will be much appreciated!