In reply to andyflem:
i'm far too much of a coward to do that....!
but with practice, and a similarly experienced partner, the rope doesn't have to slow down movement much- i remember doing the clogwyn y person arete, moving together and taking direct belays on a couple off short steeper steps, and keeping pace with the unroped party ahead of us; also a similar experience on curved ridge
(efficient movement didn't come every day though- I also remember making a mess of the upper section of dolmen ridge; after the angle eased off, the rope should have come off, instead a snail's pace faff-fest ensued...!)