I agree with lalitk. There is no need to purchase a separate server if you already own a Windows or Apple computer. I used a ten year old MacAir, on which I installed Roon Core. The resulting digital signal can be conveyed to a Roon-ready DAC (in this case PS Audio) via WIFI or USB. The sound is great, and is indistinguishable from that produced by a Roon nucleus, or any other server that has a CPU powerful enough to run Roon software.
Roon Nucleus as a Streamer
The Roon Nucleus and Nucleus+ have been recommended here as a music streamer hooked up directly to a DAC via USB or i2s. Others advise against this saying it should only be used as a music server with a dedicated music streamer in the loop. What are your thoughts?