It makes sense comparing Sony STR-DH790 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, Sony STR-DH790 has 7.2 versus 7.1 for Yamaha RX-V671. Regarding power, then STR-DH790 has such a W/Ohm ratio - 90/6 when RX-V671 has a power of 90/8, 150/4. The THD is the same and is 0.09%.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/24-bit for STR-DH790 and Burr-Brown 192 KHz/24-bit for the RX-V671. Both the STR-DH790 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.
Both models do not have WI-FI support. Rivals from our review have Bluetooth support. Each of these units does not support Apple Music. Competitors do not have built-in Spotify service. 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 RX-V671 can scale the input HDMI signal, unlike the STR-DH790. Dolby Vision technology found support only on the STR-DH790.
The Sony STR-DH790 has 4/1 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 STR-DH790. 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 RX-V671 has a built-in phono stage for connecting a vinyl player. A voice control is not available. An ECO mode is not present in each of the AV receivers. The setup assistant will help you configure Sony STR-DH790.
Only the STR-DH790 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the STR-DH790.