Full race slicks have a load more performance. A lot more.
Why? Because the compound is usually much softer and stickier, and there's no need to cut a tread on a race slick (unless it's a rain slick) - more rubber in contact with the road all the time.
Think about the contact patch of a tire. It's really quite small, even with a wide race tire. If that contact patch is really, really sticky, and isn't lessened by a cut tread pattern, well, that's about as good as it gets.
No DOT type slick will come close to a full race tire. Take a look at a race tire after its been driven through a bit of gravel and it's really apparent how much stickier they really are.