It makes sense comparing Yamaha AVENTAGE RX-A3080 vs Onkyo TX-8020 because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Yamaha AVENTAGE RX-A3080 has 9.2 versus 2.0 for Onkyo TX-8020. Regarding power, then AVENTAGE RX-A3080 has such a W/Ohm ratio - 150/8, 230/4 when TX-8020 has a power of 90/6. The THD is 0.06% for the AVENTAGE RX-A3080 but 0.03% for the TX-8020.
Characteristics of digital to analog converter (DAC) are different, ESS SABRE 384 KHz/32-bit for AVENTAGE RX-A3080 and 192 KHz/24-bit for the TX-8020. Only the AVENTAGE RX-A3080 supports Bi-amping feature. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Only the AVENTAGE RX-A3080 has Bluetooth support. The Yamaha AVENTAGE RX-A3080 has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Only the AVENTAGE RX-A3080 supports Spotify. Only the AVENTAGE RX-A3080 provides HDMI signal transmission in standby mode. The AVENTAGE RX-A3080 can scale the input HDMI signal, unlike the TX-8020. Dolby Vision technology found support only on the AVENTAGE RX-A3080. Only the AVENTAGE RX-A3080 supports HDMI Audio Return Channel (ARC). The HDMI eARC is available only on the AVENTAGE RX-A3080. Of the two receivers in our comparison, HDMI CEC is present in only the AVENTAGE RX-A3080. These compared receivers have a built-in phono stage for connecting a vinyl player. An ECO mode is only available for the AVENTAGE RX-A3080. The setup assistant will help you configure Yamaha AVENTAGE RX-A3080.
Only the AVENTAGE RX-A3080 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the AVENTAGE RX-A3080.