For non CPU intensive games its absolutely fine where games use mostly GPU but for CPU dependant games its really really bad.
But some cpu intensive games just care about single thread clock speed like arma 3 ? my quad i5 750 cannot be overlocked as i blew the keyboard fuse on my board im stuck at stock levels and arma 3 has gone from 60 fps to 20-30 fps because the clock speed isn't 4ghz + anymore.