CPUs throttle when they overheat in order to reduce the temperature and permanent damage. My AC68U & AX11000 idle at 56C with room temperature at around 15C. I don't have my AX11000 long enough to see how hot it gets in summer but my AC68U reached 80C+ in summer so I put a fan on it and the CPU temp dropped 20C+. What many people don't realise is that the CPU doesn't exist in a vacuum, the surrounding components and solder joints can fail too if the device is subjected to prolonged high temperature. Many plasma/LCD TVs have died prematurely for the same reason as they rely on passive cooling; great for the manufacturers, bad for your wallet. Heat kills electronics, just the way it is. Knowing many Asus routers have premature failures due to heat, I just put a 14cm computer case fan on top of my AX11000 and be done with it, and the CPU temp does drop 20C+ like the AC68U. But unlike most people, I setup my fans to "pull" the hot air out instead of "push" the cool air in.