SQ difference - Raspberry Pi vs x86_64?

[Snoopy8]

I have 2 Intel NUC Element, 1 with Intel® Core™ i3-8145U CPU @ 2.10GHz and another with 11th Gen Intel® Core™ i7-1165G7 @ 2.80GHz.  Also a Pi5 and a Mercury V2 streamer (CM4).  All have passive cases, run off Gieseler linear power supplies. Other than the Mercury with S/DIF outputs, all the others use USB.

Other than the room, the biggest influence on SQ is the O/S and @justme, you have come to the right place.  Then, linear power supply and various software tweaks including kernel, CPUset, Ramdisk etc.. My opinions using SnakeOil (SO) as the base

• Most of the popular Pi O/S sound worse than SO
  
• No difference between a Core i3 and 11th Gen i7 using the same software (but I have a special i7 kernel which makes a difference, which I hope AK can use to commercialize SO one day???).  Had similar findings with other NUCs, so using a low powered box did not make a difference for me
  
• NUC is slightly ahead of the Pi5 but had to look for it; in other words, the SQ difference is not night and day,
  
• Pi5 better than Pi4, based on Mercury which use the compute module CM4
  

Rather than trying to find an Intel or AMD box, suggest getting another Pi5.  It is cheaper and so much easier to put together. And backing up, changing & trying things is easy using micoSD cards. (I use Clonezilla to backup and restore NUC trials and tribulations).

To improve the Pi5, suggest getting a linear power supply or run off battery.  I was surprised that running separate boxes for LMS and Squeezelite made a difference (thank you to @hkphantomgtr).  And there is a good chance that AK will further improve things...

p/s have parked aside the influence of the room and the use of DSP to improve things.  This is a huge topic that should be discussed separately...