I spent a bunch of time researching why I was getting terrible stuttering, mouse lag, and bad FPS in Roon and since I didn’t see my solution here, I figured I’d post it for the next person.
I have 2 g-sync monitors, an Acer x34 and an Alienware AW342DW. Roon was performing perfectly on the Acer, but stuttering on the AW. After trying a bunch of manual G-Sync configurations from other support articles, I realized the only other difference was HDR on the AW. Once I disabled HDR, performance is normal on the Alienware. Hopefully this helps someone!