It makes sense comparing Denon AVR-S740H vs Onkyo TX-NR595 because they both are able to give some premium features.
Considered AV receivers have the same number of channels 7.2. Regarding power, then AVR-S740H has such a W/Ohm ratio - 75/8, 110/6 when TX-NR595 has a power of 80/8, 170/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/32-bit for AVR-S740H and AKM 384 KHz/32-bit for the TX-NR595. Only the TX-NR595 supports Bi-amping feature. 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. The Apple Music service is implemented on considered devices: AirPlay, AirPlay 2. Spotify can be used on each receiver. The AVR-S740H can work with the audio stream from Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud, and the TX-NR595 can receive a content from Deezer, TIDAL, Pandora, TuneIn Radio. Compared AV receivers retain the quality of 4K/60Hz signal when transmitting from a source to a TV or projector. HDMI signal transmission in standby mode is implemented in each of the devices. The TX-NR595 can scale the input HDMI signal, unlike the AVR-S740H. The HDR standard - Dolby Vision is supported by these receivers.
The Denon AVR-S740H has 6/1 HDMI inputs/outputs versus 6/2 HDMI connectors of the Onkyo TX-NR595. The HDMI Audio Return Channel (ARC) feature supports both devices. Unfortunately, HDMI eARC is not available on monitored devices. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. Both models support the standard HDCP 2.2. 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. The AVR-S740H supports voice control via Amazon Alexa, Google Assistant, Siri, Josh.AI, and the TX-NR595 - Google Assistant. An ECO mode is only available for the AVR-S740H. Both AVR-S740H and TX-NR595 can be configured using the Setup assistant.
Both devices have support for Dolby Atmos multichannel audio format. The surround sound technology DTS:X is supported by devices under review.