I've had problems with shutdowns over the years running 5.1 and 7.1 speaker setups and the solution was to run the front L+R speakers off an external amp. Or like I have it now, with the center running off yet another amp I had sitting doing nothing. My receiver stays at a sane temp, and no shutdowns any more. I'm running my fronts off an recapped Onkyo M-508, and the center is one channel of an old Pioneer, I can't remember the model. My Yamaha TSR-7810 (Same as an RX-V781) stays cool and with the fan unit on it, never gets above 83 F. Sadly, a lot of receivers just can't seem to handle 5 and 7 or more speakers at any real power level. My TSR-7810 weighs about 5 pounds less, mostly in the transformer and heat sinks, than the RX-V691 it replaced, I knew it wouldn't handle the stress of 7 speakers for sure, so an amp was used almost from day one. My Denon 4700X wasn't all that much better at tolerating 7 speakers than the Yamaha was/is, and I decided to keep the Yamaha, as I was familiar with it's menus and setups. I did like the sound of the Denon slightly better though, but my right ear is a mess at this point anyway...