The Denon power guarantee is for an 8 ohm nominal impedance load. Denon did not rate the AVR for 4 ohms without using the impedance setting that limits rail voltage. We all know the 4700 can handle 4 ohms speakers while leaving the default 8 ohm setting in place - provided you don't try to overdrive it.
If the Receiver goes into protection mode - as a result of over driving the speakers get an external amp or turn it down. Most speakers on the market are 4 ohms. Many 8 ohm labeled speakers reach 4 ohm loads at some point in the FR. Revel speakers are a prime example.
Heat - The
Denon 4700 runs hot when you load it up with speakers using the internal amps and run it for an extended period of time. Even if it's sitting out with open air all around it the temperature climbs. The
AC Infinity MULTIFAN S7 runs quiet on the low setting and does an excellent job of keeping the unit cool. It's a great match in my opinion.