It makes sense comparing Denon AVR-X3500H vs Denon AVR-S950H 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-X3500H has such a W/Ohm ratio - 105/8, 135/6 when AVR-S950H has a power of 90/8, 125/6. The THD is 0.05% for the AVR-X3500H but 0.08% for the AVR-S950H.
Competitors' digital to analog converter (DAC) is identical to AKM 192 KHz/32-bit. Only the AVR-X3500H supports Bi-amping feature. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing. 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-X3500H can work with the audio stream from Deezer, TIDAL, Pandora, TuneIn Radio, and the AVR-S950H can receive a content from Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud, Mood Mix.
Both AV receivers support HDR10 technology (High dynamic range). 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. Both rivals can scale the resolution of the incoming HDMI signal. The HDR standard - Dolby Vision is supported by these receivers.
The Denon AVR-X3500H has 8/3 HDMI inputs/outputs versus 8/2 HDMI connectors of the Denon AVR-S950H. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the AVR-S950H. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. The AVR-X3500H supports the protection of digital content of the standard HDCP 2.2, versus HDCP 2.3 in the AVR-S950H. 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. Supported voice control technologies are identical - Amazon Alexa, Google Assistant, Siri, Josh.AI. It is also worth noting that the ECO mode is presented in each of the receivers. Both AVR-X3500H and AVR-S950H 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.