It makes sense comparing Denon AVR-S650H vs Onkyo TX-RZ710 because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Denon AVR-S650H has 5.2 versus 7.2 for Onkyo TX-RZ710. Regarding power, then AVR-S650H has such a W/Ohm ratio - 75/8, 100/6 when TX-RZ710 has a power of 175/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, AKM 192 KHz/32-bit for AVR-S650H and AK4458 384 KHz/32-bit for the TX-RZ710. Only the TX-RZ710 supports Bi-amping feature. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Rivals from our review have Bluetooth support. The Denon AVR-S650H has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Spotify can be used on each receiver. The AVR-S650H can work with the audio stream from Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud, Mood Mix, and the TX-RZ710 can receive a content from Deezer, TIDAL, Pandora, Tunein Radio. Compared AV receivers retain the quality of 4K/60Hz signal when transmitting from a source to a TV or projector. HDMI signal transmission in standby mode is implemented in each of the devices. The TX-RZ710 can scale the input HDMI signal, unlike the AVR-S650H. Dolby Vision technology found support only on the AVR-S650H.
The Denon AVR-S650H has 5/1 HDMI inputs/outputs versus 8/2 HDMI connectors of the Onkyo TX-RZ710. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the AVR-S650H. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. The AVR-S650H supports the protection of digital content of the standard HDCP 2.3, versus HDCP 2.2 in the TX-RZ710. These compared receivers have a built-in phono stage for connecting a vinyl player. It is also worth noting that the ECO mode is presented in each of the receivers. The setup assistant will help you configure Denon AVR-S650H.
Only the TX-RZ710 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the TX-RZ710.