We saw a similar situation when AMD released the Bulldozer line of CPUs and it took a minute for Microsoft to release a Hot Fix to address the issue.

https://www.anandtech.com/show/5448/the-bulldozer-scheduling...

The reality is that Windows doesn't recognize the new CPU and so it's not using a scheduler optimized for it. Where as AMD could have upstreamed any necessary changes for Linux to fully support it months ago.