Does the shudder happen when listening to music via Windows Media Player, or is this strictly tied to YouTube's website only? Have you checked your event viewer for any errors that seem to have the same timestamp as the shudder?
Only youtube so far, and music on via soundcloud links though facebook this morning, the only thing is as its a new build i haven't got round to downloading music yet but, when i do it will be though iTunes, ill try that now with a cd or something to see if it happens?
How do i check my event viewer?
By browser is Google Chome as well