It makes sense comparing Yamaha RX-V583 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 RX-V583 has 7.2 versus 2.0 for Onkyo TX-8020. Regarding power, then RX-V583 has such a W/Ohm ratio - 80/8, 145/6 when TX-8020 has a power of 90/6. The THD is 0.09% for the RX-V583 but 0.03% for the TX-8020.
Characteristics of digital to analog converter (DAC) are different, Burr-Brown 192 KHz/24-bit for RX-V583 and 192 KHz/24-bit for the TX-8020. Only the RX-V583 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 Yamaha RX-V583 can connect to the Internet via WI-FI. Only the RX-V583 has Bluetooth support. The Apple Music service is implemented on considered devices: AirPlay. Only the RX-V583 supports Spotify. Only the RX-V583 provides HDMI signal transmission in standby mode. The RX-V583 can scale the input HDMI signal, unlike the TX-8020. Dolby Vision technology found support only on the RX-V583. Only the RX-V583 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-V583. The TX-8020 has a built-in phono stage for connecting a vinyl player. An ECO mode is only available for the RX-V583. The setup assistant will help you configure Yamaha RX-V583.
Only the RX-V583 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the RX-V583.
The Yamaha RX-V583 is better receiver in this comparison. Check Yamaha RX-V583 price