I may be wrong, as I'm not an expert but Intel E-Cores are basically decendents of Intel ATOM (I personally really liked the idea of ATOM it was just so nerfed by Intel with its memory limits and platforms) and P cores are derived from the i-Series - two totally different cores. Yes they support the same instruction sets generally, but they are different cores.
AMD's approach was to basically trim the fat on Zen as far as they possibly could but keep the core fast and efficient and you end up with the C-Cores.
In practice (where I generally live with expertise) AMD's approach lets you move software between cores and it generally doesn't care or know, whereas Intel's method applications definetly do care and can have issues.
To me, the difference is moving a virtual machine between two similar CPUs and not having to reboot it (AMDs approach) and having to reboot for one reason or another (Compatibility) -- Intels method.
AMD's approach was to basically trim the fat on Zen as far as they possibly could but keep the core fast and efficient and you end up with the C-Cores.
In practice (where I generally live with expertise) AMD's approach lets you move software between cores and it generally doesn't care or know, whereas Intel's method applications definetly do care and can have issues.
To me, the difference is moving a virtual machine between two similar CPUs and not having to reboot it (AMDs approach) and having to reboot for one reason or another (Compatibility) -- Intels method.