My game runs smoothly at around 100 fps, but when racing with AI enemies it will occasionally drop to like 50 fps, which causes stutter. Happens mostly on the long straights of any track. This happens even if I disable all antialiasing and set graphics to low. The GPU isn't maxing out, and neither is the CPU. But if I reduce the number of enemies, the problem pretty much disappears, so it's obvious what's causing the issue. I normally race with 27 enemies, is that too much for an i5 4690k? If so, why isn't the CPU maxing out?