Nah, I've tried different ram, and my previous 9900k couldn't do it either.
Wow - thank you thats the first time i can boot my 32GB 4.266Mh 17-18-38!
I already tested 5-6 Kits and 2 Maximus XI Extreme Boards and 1x 9900K and 3x9900KS CPU's!
The max what i ever could use was 4.100 16-16-36 and with a second Extreme mobo i can reach 4.133 - GSAT stable!
Now i see the first time booting with the xmp I profile the first time ever!
The funny was 4.300mhz i can boot to without any problems - but it was never GSAT stable.
Thanks for this hint - now i can test if this works GSAT, Memtest Deluxe & Kahru stable.