I have the 3.4 GHz i7 version with the 680MX. For this test, I just did a short render of a test scene in Cinema 4D that I have. This should put heavy stress on all physical and virtual cores, and a small amount of stress on the GPU. After a solid 10 minutes of the processors going at full bore, no part of the back of this thing is even warm to the touch. Parts are about skin temp, and others, like the bottom, are cold. It sounds unbelievable, but I swear that I'm telling the truth. The max CPU temp got to about 170 degrees F, but the back never got warm. There's a fair amount of warm air blowing out of the back vents, though. The fan through this process peaked at about 2100 RPM, which is less of a fan noise and more of just a soft "whoosh." More like just white noise. Certainly not too disturbing. It idles at about 1200 RPM, which, for all intents and purposes, is silent, even in a very quiet room. Some screenshots are attached just for fun, and to look at the temperatures as well. At idle, parts of the machine, namely the LCD proximity and the HDD, are too cold to even register with the sensor, and just have a "-" in the place of their temp.