Apparently there was, and probably still is (process groups): https://www.anandtech.com/show/15483/amd-threadripper-3990x-...

And here's a table about hardware restrictions for Windows 10: https://en.wikipedia.org/wiki/Windows_10_editions#Comparison...

Looks like Windows 10 Pro is limited to 128 cores / threads per CPU. Guess I was a bit off with my "bazillion" remark above, but who with access to that kind of hardware would ever want to waste it on Windows anyway?