That means a roughly 5.5GHz MT clock will go down to 4.6GHz as an example

There’s no chance that the drop will be that severe. It will be around 10%

6-20%

https://www.igorslab.de/en/intels-internal-performance-projection-for-raptor-lake-s-refresh-and-arrow-lake-s/

Not Western Digital, but Seagate has introduced HAMR HDDs

The LBR (Last Branch Record) Event Logging feature sounds really neat for optimizing branches.