What I have is a tiny 5v fan on one of the usb port opening, you can also use the gpio area opening as the vent.My temps dropped fro 79c to 67c under 100% load on all cores. I've been building linux on all four cores and everything seems stable
Which version ROM did you run when you got the temperate testing data? If you run the new official ROM Ubuntu-mate, the temperature will never up to 79 degree if without heatsink and cooling fan.
I meant to say from 76c to 67c