Hey @Stuart_Matheson — Thanks for the report!
As @wizardofoz mentioned, may I kindly ask that you please provide a brief description of your current setup using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so we can have a clear understanding of how your devices are communicating.
May I also ask that you please elaborate on the slowness you are seeing? Is it specifically in the UI (navigating in Roon), but playback is fine? Or are you having playback difficulties as well?
Have you tried rebooting your Core and any affected endpoints since noticing this behavior?
Regards,
Dylan