Here are some all channel driven test from soundandvision.. I believe, these are the only guys who have been providing all numbers in addition to audioholics..
Denon x 3400 power ratings -
https://www.soundandvision.com/content/denon-avr-x3400h-av-receiver-review-test-bench
2 Channels Continuously Driven, 8-ohm Loads: 123.0 watts
5 Channels Continuously Driven, 8-ohm Loads : 97.6 watts
7 Channels Continuously Driven, 8-ohm Loads : 72.7 watts
Denon x 1200 power ratings -
https://www.soundandvision.com/content/denon-avr-x1200w-av-receiver-review-test-bench
2 Channels Continuously Driven, 8-ohm Loads 112.8 watts
5 Channels Continuously Driven, 8-ohm Loads 69.9 watts
7 Channels Continuously Driven, 8-ohm Loads 47.4 watts
From the above numbers even if the x1200 delivers slightly lesser numbers than x 3400, it is equally good as Denon 3400 w.r.t power ratings..
Couldn't get a review link for NR series.. But as said by other FM, the power ratings would drop for all channels driven..