I made a thread about this a few weeks back, but it's on page 2 now haha.
Basically there's been no concrete answer as to whether the Z370 Maximus boards will be able to handle decent overclocks on the 9900k, but I've heard most people suggest that it will, just not extreme overclocking.
As far as I can tell, the difference in power delivery is that the Maximus XI boards have 12 power phases as well as an additional 4 pin CPU power connector, while the Maximus X have 10 power phases and the standard one 8 pin connector. It seems that the Maximus X boards are more inline with the Z390 Strix boards which appear to have 10 phase power delivery and one 8 pin connector.
Real testing and reviews should be out soon. I'm hoping to keep my MX Code if I can too haha.
