The CPU utilization of Roon is quite variable, and relative. The biggest challenges for Roon CPU are use of DSP and format conversion such as DSD to PCM or vice versa.
It's also relative to the CPU that you have. Very low power CPUs as used in micro PC's may be more stressed more easily. Also, because DSP happens on the server, if you have multiple music streams going on at once this can also increase CPU usage.
Having said all of that, the CPU usage I observe is generally very low. Not sure what this has to do with anything though, so long as the stream doesn't break up this should not affect playback quality as the Roon endpoints keep a significant buffer.