reddit has some benchmarks (rumored):
The main reason intel is getting better single-thread performance is the higher clock speeds. I think the graphs even suggest that zen is getting higher IPC.
I really doubt Intel can push the clock speeds much higher. Intel really need to find more IPC somewhere, otherwise future versions of Ryzen (Zen+, Zen++) will overtake the intel chips as AMD refine the Zen design to improve IPC and improve clock speeds at the same time.