That's what I referred to as "TRIM for RAM". I'm not aware of it being a thing. And I don't know the protocol, but I'm also not sure it's just a matter of protocol. It might require additional circuitry per bit of memory that would increase the cost.
'trim' for RAM is a virtual to physical page table hack. Memory that isn't backed by a page is just a zero, it doesn't need to be initialized. Offhand it's supposed to be before it's handed to a process, but I don't know if there are E.G. mechanisms to use some spare cycles to proactively zero non-allocated memory that's a candidate for being attached to VM space.
