An affordable AV receiver is always a good option to consider, so Denon AVR-S940H vs Onkyo TX-8140 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Denon AVR-S940H has 7.2 versus 2.0 for Onkyo TX-8140. Regarding power, then AVR-S940H has such a W/Ohm ratio - 90/8, 125/6 when TX-8140 has a power of 80/8, 110/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/32-bit for AVR-S940H and AK4458 384 KHz/32-bit for the TX-8140. 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.
Both models have the ability to connect to the Internet via WI-FI. Rivals from our review have Bluetooth support. Spotify can be used on each receiver. The AVR-S940H can work with the audio stream from Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud, and the TX-8140 can receive a content from SiriusXM. Only the AVR-S940H provides HDMI signal transmission in standby mode. The AVR-S940H can scale the input HDMI signal, unlike the TX-8140. Dolby Vision technology found support only on the AVR-S940H. Only the AVR-S940H 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 AVR-S940H. These compared receivers have a built-in phono stage for connecting a vinyl player. An ECO mode is only available for the AVR-S940H. Both AVR-S940H and TX-8140 can be configured using the Setup assistant.
Only the AVR-S940H has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the AVR-S940H.