VideoCardz posted a copy of the CineBench R15 results. The six-core, twelve-threaded chip achieves a multi-core score of 1230 points, which is roughly a quarter higher than what a Core i7-7700K achieves. The multi-core performance is of course a lot higher as Intel is making the switch from quad-core to six-core for its Core i7 series.
MrTechQc also tested single-core performance and this resulted in 196 points, which is just a couple of points more than a Core i7-7700K.
Intel's Coffee Lake-S desktop CPUs are expected on October 5, 2017.