So my girl loaned me her Air for the next few weeks (long story short: I have a huge, life-determining computer based exam coming up, so I need a computer for studying. Her computer is awesome, she's awesome, and my old windows laptop is well, old, and windows, and I need to study out of the house but my laptop's battery, well, is also old.) Now, before it sounds like I'm complaining, I'll first state that I love this thing, but I'm having trouble playing any of my 720p mkv files with it. Whether I'm hooked up to my external monitor or playing on the air by itself it just chugs. Gets about 15 seconds in and starts dropping frames left and right. Tried in VLC, no better. It plays DivX files ok, unless I output them to the external monitor, then those play pretty laggy. And I opened activity monitor, noticed that the 2nd core had shut down. Not to mention that this thing was scalding hot. So is this related to overheating alone, or is this due to bad video codecs? The thing is that my old tiny laptop, a 12" dell 700m with a 2.0 ghz pentium M, intel 855 graphics, and 1 gig of ram, could play those 720p files without a problem. It's 30 months old. This thing is 4 months old. I know it's ultra-portable, but so was that one, it'd be a huge shame if the 1.6 core 2 duo and x3100 graphics couldn't do better. 2nd question: Will this happen with a macbook pro? I'd been planning on getting one around the fall for a while now, but a lot of my video collection is 720p-1080p, so I'd hate for that to be the case... I can't imagine it would.