Which device makes for a better digital music source? Computer or streamer?

Streamers are indeed computers, but run relatively few processes which means less noise generated. Add better rendering capabilities vs most computers, servers/streamers, wins on two counts. Streaming dacs are also nice, foregoes external rendering which can be advantage.

Stands to reason streamer generally going to be superior to most server/streamer combo and far superior to general purpose computer. Noise is the enemy, segregating streamer from server or computer results in least amount of noise just prior to dac, certainly one of the most important links in network chain.

I really prefer no rendering taking place within servers, in this way they become simple network devices, minimize signature on sound quality.

On the apple front I can add some input. I've used various iterations of mac mini as server over the years. In order of sound quality, worst to best.

1. 2009 Stock mini, no optimization of OS, usb out.

2. 2009 Stock mini, partially optimized OS (some processes disabled), usb out

3. 2014 mini, I5 Intel, El Capitan OS, sata ssd, Uptone MMK and JS2, usb out, major upgrade on above, really in different league.

4. 2014 mini, same as above with some optimization (again, some processes disabled), Uptone usbRegen, nice upgrade on above

5. 2014 mini, same as above with more optimization (go into terminal and shut down more processes), thunderbolt bridge for network out vs usb out. At this point requirement to go to streamer, in this case SOtM SMS 200 Neo.This is major, major upgrade, eliminating usb rendering within server lowers noise floor greatly.

6. Same as above, add generic FMC just prior to SOTM, more lowering of noise floor, very worthwhile upgrade

2014 mini, I7 Intel PCIe ssd, Monterey OS, Uptone MMK and JS2, 3rd party wipe of unneeded apps, disable system integrity protection. Still using FMC and SOTM as streamer, pretty substantial upgrade over I5 and sata ssd. Faster processor and PCIe vs sata very nice, disabled SIP absolute necessity.

7. Same exact sertup as 6. Replace SOTM with Sonore OpticalRendu, major upgrade, further lowering of noise floor, jitter, sound quality entering realm of extremely nice analog.

Concurrent, to above mini upgrades has been continuing network upgrades, all contributed to gradual lowering of noise floor.

My analysis of servers/streamers at this point. Faster processor, OS optimization and ssd quality critical for server. Streamer quality critical as well as entire network. But for me, greatest upgrade was eliminating all rendering from server. Servers are likely noisiest component in streaming chain (router up there), not good place to do rendering with exception of the rare server that has fully optimized internal rendering. IMO, server is best as simple network device, dedicated streamer or streamer dac place to do rendering. Exception would be atx motherboard based servers with Pink Faun, JCAT usb cards, or exceptional servers such as Wadax.