Volumio stutters via HDMI

I own a raspberry Pi2 with a HiFiBerry Dac Plus and a run-of-the-mill raspberry Pi3

I flashed Volumio version 2.699 (Relased Mon Jan 20 19:41:22 CET 2020) to a Sandisk Ultra 16GB class 10 card and inserted it into my Pi3. I attached the Pi3 to an Onkyo TX-SR444 7.1 A/V Receiver using a 1.4 HDMI cable. In Volumio I mounted my Synology DS118 single-bay Nas via SMB and started playing the mp3 320 encoded music. There was a lot of audio stuttering.

Maybe the NAS was the culprit so I changed the SMB mount to a NFS mount, a file system that is supposed to handle smaller files better. No dice. Maybe the shared USB/ethernet bus was the culprit ? I tried playing the music from an attached powered USB disk and from a USB stickā€¦still stuttering.

I moved the SD card to my raspberry Pi2, lower specs than the 3 but it uses a HiFiBerry Dac Plus as output rather than the HMI out on the Pi3. Playing the same audio, from the same nfs mounted source, attached to the same Onkyo TX-SR444 7.1 A/V Receiver but this time via an analog input resulted in no more audio stuttering.

I was wondering, does HDMI-out require so much from the Pi3 that it creates audio stutters ?