It makes sense comparing Onkyo TX-RZ920 vs Yamaha RX-V671 because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Onkyo TX-RZ920 has 9.2 versus 7.1 for Yamaha RX-V671. Regarding power, then TX-RZ920 has such a W/Ohm ratio - 135/8, 175/6 when RX-V671 has a power of 90/8, 150/4. The THD is 0.04% for the TX-RZ920 but 0.09% for the RX-V671.
Characteristics of digital to analog converter (DAC) are different, AK4490 384 KHz/32-bit for TX-RZ920 and Burr-Brown 192 KHz/24-bit for the RX-V671. Both the TX-RZ920 and the RX-V671 support Bi-amping. 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. Only the TX-RZ920 supports Spotify. The TX-RZ920 can work with the audio stream from Deezer, TIDAL, Pandora, TuneIn Radio, and the RX-V671 can receive a content from Napster. 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. Both rivals can scale the resolution of the incoming HDMI signal. Dolby Vision technology found support only on the TX-RZ920.
The Onkyo TX-RZ920 has 8/2 HDMI inputs/outputs versus 6/1 HDMI connectors of the Yamaha RX-V671. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the TX-RZ920. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. Both models support the standard HDCP 2.2. These compared receivers have a built-in phono stage for connecting a vinyl player.
The TX-RZ920 supports 3 Multi-room zones, versus 2 for the RX-V671. An ECO mode is not present in each of the AV receivers. The setup assistant will help you configure Onkyo TX-RZ920.
Only the TX-RZ920 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the TX-RZ920.