Operating systems already tier
All the major OS preload expected data from disk into RAM, and eject unused pages back to disk when RAM is low.
They also choose cores to schedule based on what is probably in the upper levels of CPU cache, to avoid copying between sockets etc.
They would certainly be better at choosing what should go in the "fast" RAM and what can stay in the "slow" than any firmware level memory manager ever could.
Let them, Intel!