It makes sense comparing Yamaha RX-V671 vs Onkyo TX-8260 because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Yamaha RX-V671 has 7.1 versus 2.0 for Onkyo TX-8260. Regarding power, then RX-V671 has such a W/Ohm ratio - 90/8, 150/4 when TX-8260 has a power of 80/8, 160/6. The THD is the same and is 0.09%.
Characteristics of digital to analog converter (DAC) are different, Burr-Brown 192 KHz/24-bit for RX-V671 and AK4452 384 KHz/32-bit for the TX-8260. Only the RX-V671 supports Bi-amping feature. The Yamaha RX-V671 can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Only the Onkyo TX-8260 can connect to the Internet via WI-FI. Rivals from our review have Bluetooth support. Only the TX-8260 supports Spotify. The RX-V671 can work with the audio stream from Napster, and the TX-8260 can receive a content from TIDAL, Pandora, TuneIn Radio.
HDR is not available on each model. Only the RX-V671 provides HDMI signal transmission in standby mode. The RX-V671 can scale the input HDMI signal, unlike the TX-8260. The HDR standard - Dolby Vision is not supported by these receivers. Only the RX-V671 supports HDMI Audio Return Channel (ARC). Unfortunately, HDMI eARC is not available on monitored devices. Of the two receivers in our comparison, HDMI CEC is present in only the RX-V671. These compared receivers have a built-in phono stage for connecting a vinyl player.
Each of the AV receivers from our review supports 2 Multi-room zones. A voice control is not available. An ECO mode is not present in each of the AV receivers. Unfortunately, the setup assistant is not available in each of the models.
None of the rivals equipped with Dolby Atmos multichannel audio decoder. The receivers do not support the surround sound technology DTS:X.