periodic 12 second XP audio glitch

Hello all,
In the last two months or so, every 12 seconds or so of audio output, I get about two seconds of distortion coming from max. I'm running 4.6.2 on a core 2 duo T5200 processor with XP MCE SP2, and don't have any audio output problems with Ableton Live, Propellorhad's Reason, ITunes, or any other audio program. I've attached an mp3 of the distortion, created with the patch below. The first part of the mp3 is what max hears; it was recorded with sfrecord~. The second part of the mp3 is what I hear, recorded in another program. As you can hear, max doesn't internally register any distortion either in the sfrecord~ file or visually in scope~, which is flat while I hear the distortion.

Any ideas or diagnostic tests anyone can suggest?
Myer