Some examples described herein relate to redundancy in a multi-chip stacked device. An example described herein is a multi-chip device. The multi-chip device includes a chip stack including vertically stacked chips. Neighboring pairs of the chips are directly connected together. Each of two or more of the chips includes a processing integrated circuit. The chip stack is configurable to operate a subset of functionality of the processing integrated circuits of the two or more of the chips when any portion of the processing integrated circuits is defective.