This came out of left field when I was installing Windows 7 on BootCamp partition. The system shut-down in the middle of the install and the MINI was burning hot to the touch, so I tried installing Windows 7 again with the cover off and a fan blowing at the MINI to see if it helped. When all was said and done, I rebooted into Lion with the cover off, and to my surprise the CPU is registering a good 10 degrees cooler than what I'm used to seeing. So I turned off the fan blowing at the Mini, turned it off, and waited for everything to cool down, restarted it and sure enough, the temperature was pretty stable at 45º C (no cover) vs. 55º C (cover) with light to no load and the internal fan blowing at 2,500 RPM. I've drilled two small holes around where the fan sits on the cover to see if the cooling effect of ambient air through the fan will help, and it appears having access to outside air helps the fan cool down the CPU considerably. Now with the cover back on the CPU sits pretty stable between 45ºC-47ºC as long as I'm not encoding video. Just another datapoint to the intel i5/i7 temperature debate on the MINI. p.s.: I ran the Mini standing on its side most of the time to save space on a very small desktop dominated by a large Wacom tablet.