Well you have to take some early results with a grain of salt. Drivers, updates, and firmware, and the software itself can be a big factor.
Tom's review of the 7700k revealed very high temps on one motherboard and good results on another. Soon as the BIOS updates hit the shelves for older boards and the kinks worked out of the new products, you'll probably see the normal 5-10% increase.
I plan on picking one up. Kind of curious to play with Optane but really just want an NVMe drive and a chip that doesn't hate overclocking as much as mine.