Understanding Logical Processors

Logical processors subdivide a server’s processing power to enable parallel processing. Shown here is a server with two physical processors with a view of how the OS recognizes the resulting logical processors.

A physical processor, also referred to as a CPU, socket, or occasionally as a package, is a chip visible on a computer’s circuit board. Modern physical processors have multiple cores, which are independent processing units. Typical servers will have multiple physical processors with as many as 12 cores.

A logical processor is a unit in the Windows OS that is capable of executing its own stream of instructions and which the OS can assign to independent pieces of work. Windows Server enables each core to appear as a logical processor, so the server shown here, which has two quad-core physical processors, can have eight logical processors. Some processors support a technology called symmetric multithreading (which Intel calls “hyperthreading”), which enables a core to execute two independent instruction streams; if the technology were enabled here, the result would be 16 logical processors.