My guess is an architecture change that allows more of the 'shared' resources to be used by a single core rather than rigidly enforcing a subdivision of the res

My guess is an architecture change that allows more of the 'shared' resources to be used by a single core rather than rigidly enforcing a subdivision of the resources between each core. Sort of like if you had 2MB of cache per core vs a shared 8MB cache between 4 cores.