Not to mention that I believe the QNAP SOHO units are doing software RAID, and that can certainly use some processor cycles.
However, if you are canny enough however you can upgrade the processor (so long as you respect the TDP) and memory in many of the units
The optimal Roon installation will be a headless Roon server (to be released in the foreseeable future it seems) tucked away somewhere, data on a NAS or equivalent mass store and various endpoints as needed.
I do sometimes wonder what the take up numbers would have been if Meridian had introduced Roon as Sooloos 3 and said:
"The Software itself is FREE... while it will cost £1,000 to Upgrade your MC200... £1,250 to Upgrade your MD600... and £2,000 to Upgrade your Control:15... in order to run the New Sooloos App."
This is Meridian we're talking about here... who have never been reticent about their pricing points... even my prices above were being very conservative on how much Meridian are likely to have charged for the necessary hardware modifications plus Labour Time to carry out the upgrades.
But even if I take the suggested £850, that is roundabout the price required to buy a Lifetime Sub to Roon plus a PC to run the Server / Core on.
Plus there is the initially cheaper annual sub route option for Roon.
And it also assumes that the User doesn't have a PC suitable to run Roon already in their homes... which has been the case for many.