Methods and apparatus related to PCMS (Phase Change Memory with Switch) write error detection are described. In one embodiment, a first storage unit stores a single bit to indicate whether an error corresponding to a write operation in any of one or more PCMS devices has occurred. Also, one or more storage units each store a plurality of bits to indicate whether the error corresponding to the write operation has occurred in a partition of a plurality of partitions of the one or more PCMS devices. Other embodiments are also disclosed and claimed.