It makes sense comparing Yamaha CX-A5200 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 CX-A5200 has 11.2 versus 2.0 for Onkyo TX-8020. The THD is 0.06% for the CX-A5200 but 0.03% for the TX-8020.
Characteristics of digital to analog converter (DAC) are different, ESS SABRE PRO (ES9026) 384 KHz/32-bit for CX-A5200 and 192 KHz/24-bit for the TX-8020. None of the models support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Only the CX-A5200 has Bluetooth support. The Yamaha CX-A5200 has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Only the CX-A5200 supports Spotify. Only the CX-A5200 provides HDMI signal transmission in standby mode. The CX-A5200 can scale the input HDMI signal, unlike the TX-8020. Dolby Vision technology found support only on the CX-A5200. Only the CX-A5200 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 CX-A5200. These compared receivers have a built-in phono stage for connecting a vinyl player. An ECO mode is only available for the CX-A5200. The setup assistant will help you configure Yamaha CX-A5200.
Only the CX-A5200 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the CX-A5200.