An administrator has a mixture of Intel-based ESX Hosts in a DRS cluster where the
CPUs are compatible in every way except that some support the NX/XD feature and
some do not. What can you do to minimize the effect of these differences (Choose Two)?

A.
Mask the NX/XD bit in the Processor section of the Configuration tab on the ESX
Hosts

B.
Mask the NX/XD bit on every virtual machine in the cluster

C.
Enable Rapid Virtualization Indexing

D.
Enable enhanced VMotion compatibility

Explanation:
vSphere Basic System Administration vCenter Server 4.0 ESX 4.0 ESXi 4.0, page 153.
Select Advanced > CPUID Mask.
1. Specify whether you want to hide the host’s CPU NX flag from the guest operating
system
Hiding the NX flag prevents the guest operating system from making use of this CPU
feature, but enables the virtual machine to be moved to hosts that do not include the NX
feature. When the NX flag is visible, the guest operating system can make use of the
feature, but the virtual machine can be moved only to hosts with the NX capability.
Enhanced VMotion Compatibility (EVC) processor support
Enhanced VMotion Compatibility (EVC) simplifies VMotion compatibility issues across
CPU generations. EVC automatically configures server CPUs with Intel FlexMigration
or AMD-V Extended Migration technologies to be compatible with older servers. After
EVC is enabled for a cluster in the VirtualCenter inventory, all hosts in that cluster are
configured to present identical CPU features and ensure CPU compatibility for VMotion.
The features presented by each host are determined by selecting a predefined EVC
baseline.