A:Answer Dear All, please do not change the facts.
Both Denon AVR-X4300 AND AVR-X4500 have got two cooling fans.
They are located under the radiators. They can be seen by looking from above of the enclosure. At my AVR-X4300 they start to operate when I do listen very loud (above 70 on the volume knob) at 5.1 (DD, Dolby Surround or All zones stereo). They are almost silent. When they operate the enclosure is about 55 Celsius degrees (I have measured it by a termocouple).
I have been using 4 Ohms cabinets together with ECO mode switched OFF and I always play full range (no bass management, just full power, full frequency to all loudspeakers) with additional bass/treble gain in EQ. I use 8 Ohms setup (putting < an > for 3 seconds and you can find if the amp will be set to 4, 6 or 8 Ohms speakers).
Greatings for all - please verify each information found on the web. Take a look onto pictures of the Denons or any other equipment when it comes to issues like "does this audio has or has not something iniside" :)