geekyDoh. That took me at least 3 months to find out what made my machine do really odd things when I was doing large file transfers and playing music at the same time... It was worse, of course, as it was one of the disks in my RAID array, so caused problems when the array resynced every few minutes. So I only had to reinstall Windows once after trashing the RAID drivers in a futile attempt to get rid of the horrible noises and the speed issues...
Still, now I can play music happily - and have moved the entire 32849 tracks onto the server as well...
