The CPUID instruction can be used to obtain a logical processor's family, model, and stepping information. It is possible, but not guaranteed, that logical processors that report differing information might coexist on a single system. To properly use this information, a partition must be able to execute with a hard affinity between virtual and logical processors. Only the root partition executes in this manner. As a result, the hypervisor will expose the true family, model, and stepping only to the root partition and will report the minimum value that is detected in the logical processor configuration to all other partitions.

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Build date: 11/16/2013