News Intel Alder Lake-HX Leak: 16 Cores, 5 GHz Boost Clock

...If we disregard the Gracemont cores,...
How could you willy-nilly disregard the cores? If the 12900K didn't have those 8 gracemont core it wouldn't have been able beat the 16 core 5950X in most multi-threaded workloads. So those 8 gracemont must be doing something.
 
The problem here is thermals. Intel can get away with high thermals on a desktop, but not so in a laptop. Especially when people expects slimmer laptop chassis while maintaining high performance. The supposed “up to 5Ghz” is more like a rare boost, which will not benefit a sustained CPU heavy workload. So these are more like marketing and of any practical purpose.
 
The problem here is thermals. Intel can get away with high thermals on a desktop, but not so in a laptop. Especially when people expects slimmer laptop chassis while maintaining high performance. The supposed “up to 5Ghz” is more like a rare boost, which will not benefit a sustained CPU heavy workload. So these are more like marketing and of any practical purpose.
Most practical purposes, particularly on laptops, are intermittent bursts rather than than steady-state. High short-term boosts give excellent practical performance benefits there, as your primary metric is task completion time (i.e. 'responsiveness').
Almost any desktop CPU downvolted and downclocked enough could beat a stock laptop CPU in energy efficiency and overall TDP metrics, but perceptual performance in use would be pretty crap due to having to wait longer for each individual task to complete.
CPU designers (Intel, AMD, ARM, Apple, etc) have all adopted clock boosting - under various brand-names - because it works very well.