According to the Migration to a different processor web search result2, live migration of VMs depends on the source and destination hosts having the same CPU functions (CPU flags). Live migration requires the source and destination hosts to have CPUs from the same manufacturer, and only CPU functions which both hosts support areprovided (same CPU generation, or by using VMware Enhanced vMotion Compatibility (EVC)). If the administrator adds a node with older generation processors to an existing AHV cluster with newer generation processors, then live migration of VMs is prevented between newer and older processors, unless EVC is enabled.