Roon is a little unusual in that all the DSP is done by the core. So, upsampling and EQ and room correction happen there. If you are using a few EQ bands, with PCM to PCM upsampling the CPU is very little. On the other hand, upsampling to DSD can be ferocious in terms of CPU usage. I use about 6 EQ bands and double the incoming PCM rate and my 7 year old AMD A10 CPU barely hits 5% usage.
Which to use? I don't know, but not all upsampling is equivalent. The algorithms can result in different results.
Which to use? I don't know, but not all upsampling is equivalent. The algorithms can result in different results.