I recently bought two Macbook Pro Retina's for work (both are the same spec, 2.6/16GB/256GB). I've installed the exact same software on both and when I run them next to each other, I can see one is running about 30 deg F hotter than the other one. The hotter one also has problems running my home monitor configuration which comprises of 2 1600x1200 Dell 2007FP with a 2560x1600 Dell U3011. I've turned off the Retina display itself (using SwitchResX so I can keep the lid open to let it vent - not sure if that really turns the monitor off or just covers it with a black screen since I still see a backlight). In this configuration, the computer never goes below 180 deg F, which means that as soon as I start doing stuff, the fans start revving and eventually it starts throttling. I took the hotter one to Apple (I got AppleCare on both) and they ran the Cooling test and it came back OK. Are these just standard manufacturing differences? I'm considering re-applying the thermal paste in the hotter one (that's the only thing I can think of that's making such a difference) but I don't know if that really helps the resting temperature or the temperatures under load. Also, even though I'm comfortable with the procedure, I'd prefer to not take the risk if it was unlikely to help. Any ideas? Are there configuration things that I might have overlooked that would cause such a temperature difference? I'm using iStat Menus to monitor the temperature.