Thanks Paul. I think it may be one of those things that's just down to hardware intricacies. And thanks Hartmut. Lots of good info for me to look into. I've tried various distros (I'm on KXStudio currently and it's the best so far). I just tried a live-DVD of Puredyne (got more xruns than KX) and I'm downloading AV Linux to give it a go. But I'll also investigate some of the more technical recommendations you gave. It's only because I have some kind of perfectionist/purist/OCD thing that I care about these xruns. They don't (so far) happen during use, only when loading and closing certain applications. I can live with that if need be, but I love when operations are smooth and neat. -Dan