The ProcessorId property contains processor-specific information that describes the processor's features. For x86 class CPUs, ...

The ProcessorId property contains processor-specific information that describes the processor's features. For x86 class CPUs, the field's format depends on the processor's support of the CPUID instruction. If the instruction is supported, the ProcessorId property contains two DWORD-formatted values. The first (offsets 08h-0Bh) is the EAX value returned by a CPUID instruction with input EAX set to 1. The second (offsets 0Ch-0Fh) is the EDX value returned by that instruction. Only the first two bytes of the ProcessorID property are significant (all others are set to 0) and contain (in WORD-format) the contents of the DX register at CPU reset.