Picking up the 9900K this evening....will be testing the chip out on the Asus Z370 Maximus X Code....will be interesting to see the performance and temps .
From what all the reviews say the new chips get hot quick so I am thinking that as long as you have an ROG Maximus board the Z370 will be just fine and OC the CPU the same, memory compatibility and overclocking may be better, improved USB 3.1 v2, Wifi, BT, better etc. But we will see soon.
I have a 360 rad on my test bench to test ambient water and a chiller to connect for a little better temps but no Extreme cooling to get the big OC
Then I'll put it in a case with an AIO to test a more average build that most people use to help new builders on advice