I was getting frequent audible slipped buffers on a laptop host I'm testing. Nothing I tried was working, I did Bob's tweaks, did all the Black Viper service tweaks in increasing order until I was running it on his barebones settings with maybe 5 active services. Was still getting slipped buffers.
So as a last ditch effort I took out the battery to see if the charging cycle had anything to do with it.
Now, (knock on wood) I'm running at 80% with no slipped buffers for 4 hours straight.
So maybe all you laptop host guys can give it a shot and see if it helps you too.