What's the use of filling your ram with zeros when the data needs to be on L1, L2 or L3? Unless you are memsetting hundreds of MBs of memory, memset/memcpy in practice need to be handled by the cpu or something very close to it.
Zen has CLZERO which can clear a cacheline in one go, but not sure how good it is.
Zen has CLZERO which can clear a cacheline in one go, but not sure how good it is.