vMotion allows running virtual machines to be migrated between vSphere hosts. To facilitate live vMotion, the processors between hosts must contain the same CPU features and present the same instruction sets. Enhanced vMotion Compatibility (EVC) masks compatibility issues between the hosts in a cluster.
Enabling EVC on a cluster ensures that hosts that are added to the cluster in the future will not have vMotion compatibility issues.
Processors must be from the same manufacturer; EVC does not provide vMotion compatibility between Intel and AMD processors. EVC is not required to support HA across different processor types and only supports live vMotion between hosts.