If you look at my "spoiler" you see that with this setup I can run highest graphics setting on 3440x1440 at 100Hz.
Regarding CPU, Raceroom is an unusual case these days because it basically only uses one core, so single core performance should be your priority over core count. Although it's true for most videogames anyway...
AMD Ryzen 7 3700x with GTX 1060 6 GB, 1080p, 27" @144hz, 32 GB Ram all maxed out, 75 AI at NoS between between 60 -100 FPS (Start and during Race)
My system runs graphics at full bore with triple 27 inch monitors @ 144Hz, and other programs while streaming. See my sig for specs. Albeit I'm also water cooled so keep that in mind.