I have a brand new 2012 13-inch Air i5 / 4 GB / 128 SSD. It seems to pause / stutter / freeze for a fraction of a second very often when doing non-intensive everyday tasks. It is especially bad when typing (on any programme). I'll type, then every minute or so it the words on the screen take 1/4 second to catch up with what I'm typing. I'm only an average typist, not a speed demon. It's especially bad when pressing the delete key. Also, when opening programmes, switching windows, zooming, etc there is a noticeable pause. Previously, I had a 13-inch 2010 Air, 13-inch 2011 Pro, and 21.5-inch 2011 iMac. I never had any of these problems on those machines, so I know it's not me. It was doing all of this when factory fresh (i.e. a couple of days ago) without anything installed, so I don't think it's my software or set up either. I'm wondering if it's related to the graphics card. Sometimes, when typing I can just see it trying to render something on the screen before the typing appears, if this makes sense. Any ideas, do I have a dud? I'm already on my second return, I don't really wish to return again.