Denon AVR-X4100W vs Onkyo TX-RZ840 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Denon AVR-X4100W has 7.2 versus 9.2 for Onkyo TX-RZ840. Regarding power, then AVR-X4100W has such a W/Ohm ratio - 125/8, 165/6 when TX-RZ840 has a power of 180/6. The THD is 0.05% for the AVR-X4100W but 0.08% for the TX-RZ840.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/24-bit for AVR-X4100W and AKM 384 KHz/32-bit for the TX-RZ840. Both the AVR-X4100W and the TX-RZ840 support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Both models have the ability to connect to the Internet via WI-FI. Rivals from our review have Bluetooth support. The Denon AVR-X4100W has support for AirPlay, and its competitor in our comparison - AirPlay, AirPlay 2. Spotify can be used on each receiver. The AVR-X4100W can work with the audio stream from Pandora, SiriusXM, and the TX-RZ840 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 AVR-X4100W can scale the input HDMI signal, unlike the TX-RZ840. The HDR standard - Dolby Vision is supported by these receivers.
The Denon AVR-X4100W has 8/3 HDMI inputs/outputs versus 7/2 HDMI connectors of the Onkyo TX-RZ840. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the TX-RZ840. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. These compared receivers have a built-in phono stage for connecting a vinyl player.
Each of the AV receivers from our review supports 3 Multi-room zones. An ECO mode is only available for the AVR-X4100W. Both AVR-X4100W and TX-RZ840 can be configured using the Setup assistant.
Both devices have support for Dolby Atmos multichannel audio format. A surround technology DTS:X is supported only by the TX-RZ840.