To check the number of cores for a CPU in a virtual machine, you can use one of these utilities:

• Coreinfo
  Coreinfo is a Microsoft command-line utility, developed by Mark Russinovich. It displays the mapping between logical processors and the physical processor, NUMA node, and socket on which they reside. It also provides information on the cache assigned to each logical processor.
  
  To check the distribution of cores across socket, use the coreinfo -c -s command. To download and install coreinfo, click here.

• CPU-Z utility
  CPU-Z is a freeware application for Microsoft Windows operating systems and it provides information about CPU, Processor, Cache, Memory, System board, Graphics, and other hardware features. To download and install CPU-Z, see http://www.cpuid.com/.

In the figure below, the cpuid.coresPerSocket is set to 4 and, therefore, the number of cores per CPU is 4.

 

 

For information about setting the number of cores per socket in a virtual machine, see Setting the number of cores per CPU in a virtual machine (1010184).

Additional Information

• CPU – Is the portion of a computer system that performs the instructions of a computer program. It is the primary element that carries out the computer’s functions. 
• Core – Is a logical execution unit containing an L1 cache and functional units needed to execute programs. Cores can independently execute programs or threads. 
• Socket – Is a physical connector on a computer motherboard that accepts a single physical chip.