It makes sense comparing Yamaha RX-V481BL vs Onkyo TX-RZ630 because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Yamaha RX-V481BL has 5.1 versus 9.2 for Onkyo TX-RZ630. Regarding power, then RX-V481BL has such a W/Ohm ratio - 80/6 when TX-RZ630 has a power of 90/8, 215/6. The THD is 0.09% for the RX-V481BL but 0.08% for the TX-RZ630.
Characteristics of digital to analog converter (DAC) are different, Burr-Brown 192 KHz/24-bit for RX-V481BL and AK4458 384 KHz/32-bit for the TX-RZ630. Both the RX-V481BL and the TX-RZ630 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. The Apple Music service is implemented on considered devices: AirPlay. Spotify can be used on each receiver. The RX-V481BL can work with the audio stream from Pandora, Qobuz, JUKE, and the TX-RZ630 can receive a content from Deezer, TIDAL, Pandora. 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 competitors are not able to scale the HDMI signal. Dolby Vision technology found support only on the TX-RZ630.
The Yamaha RX-V481BL has 4/1 HDMI inputs/outputs versus 7/2 HDMI connectors of the Onkyo TX-RZ630. The HDMI Audio Return Channel (ARC) feature supports both devices. Unfortunately, HDMI eARC is not available on monitored devices. 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. The TX-RZ630 has a built-in phono stage for connecting a vinyl player. An ECO mode is only available for the RX-V481BL. Both RX-V481BL and TX-RZ630 can be configured using the Setup assistant.
Only the TX-RZ630 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the TX-RZ630.