With EVC is it possible to combine different processor generations in a cluster and still make sure that virtual machines can be moved from one ESXi host to another using vMotion. EVC masks the new processor functionality for the virtual machines in the cluster. However the new processor features are not disabled.
It is understandable that EVC has impact on only the new processor features such as AMD and SSE instructions. EVC has no effect on processor speed and processor cache levels. Hardware virtualization technologies such as Intel and AMD RVI EPT will still be available for the VMkernel if EVC is enabled.