Skylake-X Refresh isn't that bad in gaming. It's faster than the 2700X in general... beating Matisse is another story, but what the gap would be is hard to tell since so few reviewers included it, and the one I looked at (Computerbase) gave the 9900X and 9800X 2400 Mhz memory for some reason.
Yeah, but the 9900K made X299 mostly irrelevant, except for extreme use cases...