Long incessant pauses?

[thedonkeyvote]

When I play alpha 111, the game has these pauses seemingly at random. The fps drops from 160 (what's shown on the last rendered frame) to nil. This lasts up to 20 seconds and can happen a few times a minute, mucking around in this game is heaps of fun but its so annoying.
I tried turning on vsync and no dice.
Core 2 duo 3.2 ghz
460GTX 712mb
3gb ram
Windows xp 32bit

Edit: Now it has inexplicably fixed itself. Back to rabbit-fu!
Edit2: Hmm, its back almost as soon as I posted that, on the console it has something about appinputfocus lost and then regained during the lockups.