So today I tried running video on battery:
I have a ~7.5 minute .flv video of some crazy Canadian traction-kite skiers, playing in VLC maximized (cmd-3). Installed the Hardware Monitor app someone linked on page 3 here, set up the history that way. Played the video, and just hit the play and then cmd-3 after it finishes each time. After 15-20 minutes, the 'CPU A' sensor had gone from ~36C to ~53C, and it's been hovering between 50C-53C since. The fan is making no appreciable noise. If I hold the MBA up with my ear near the rear vents, I can hear an electric motor noise, not sure if that's the HD or the fan... This software wants me to buy it before it'll do fan monitoring. If it's the fan, it is running pretty slow. I can't feel a breeze coming out the back, and I have been able to when I've had the fan come on in the past (mostly editing/exporting video in iMovie).
Doing this for about 40 mins, battery went from 55% to 35%, with wireless/bluetooth off, screen at 2/3 full bright, headphones in and volume settings fairly low.
It does seem to be taking it awhile to cool off. Probably because it's not spinning the fan up. I found a tool called Fan Control, maybe I'll play with that a bit later. After about 10 minutes, CPU's down to ~44C. A little on the warm side, but considering this thing is dead quiet, not surprising.
I've had nothing but good things from my MB Air. From the sounds of it there are definately some build-quality issues with the product still, but if you get a good one, it's a great machine.
--
Alkiera