What kind of difference over the 8500 did the two Denons have?
I was just being facetious about the external amps....sort of
I can only quote the tests done by Audiovision.de (German), while they don't tell us about how they test, I think it is still useful for comparison purposes, so here are the numbers:
AVC-X8500H....................... Stereo, 260 W (4 ohm, 1 kHz Sine), 5 channel driven 181 W 4 ohms
AVC-A110............................Stereo, 277 W, 5 channel driven, 198 W, 4 ohms
AVC-A1H............................. Stereo, 287 W, 5 channel driven, 204 W, 4 ohms, 7 channel driven, 153 W, 6 ohms
The AVC-A1H's numbers were not published but you can buy the test report, that is not available for us NA readers, but an ASR member bought it (sort of for me..).
So you can see that for real world use, they are all the same, that is, all within less than 1 dB difference. It also mean for real world use, they are as powerful, in not more so, than many of the external power amps rated 150 to 180 W 8 ohms, unless the user crank it up even when listening to party music via 4 ohm speakers.