It makes sense comparing Yamaha RX-V675 vs Onkyo TX-NR595 because they both are able to give some premium features.
Considered AV receivers have the same number of channels 7.2. Regarding power, then RX-V675 has such a W/Ohm ratio - 90/8, 150/4 when TX-NR595 has a power of 80/8, 170/6. The THD is 0.09% for the RX-V675 but 0.08% for the TX-NR595.
Characteristics of digital to analog converter (DAC) are different, Burr-Brown 192 KHz/24-bit for RX-V675 and AKM 384 KHz/32-bit for the TX-NR595. Both the RX-V675 and the TX-NR595 support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Only the Onkyo TX-NR595 can connect to the Internet via WI-FI. Rivals from our review have Bluetooth support. The Yamaha RX-V675 has support for AirPlay, and its competitor in our comparison - AirPlay, AirPlay 2. Spotify can be used on each receiver. The RX-V675 can work with the audio stream from Napster, and the TX-NR595 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. Both rivals can scale the resolution of the incoming HDMI signal. The HDR standard - Dolby Vision is supported by these receivers.
The Yamaha RX-V675 has 6/1 HDMI inputs/outputs versus 6/2 HDMI connectors of the Onkyo TX-NR595. 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-NR595 has a built-in phono stage for connecting a vinyl player.
Each of the AV receivers from our review supports 2 Multi-room zones. An ECO mode is only available for the RX-V675. The setup assistant will help you configure Onkyo TX-NR595.
Only the TX-NR595 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the TX-NR595.