What Is Physical Socket, Physical Core And Logical Processor?

Intel microarchitecture history
(Image credit: Wikipedia)

Back in the old days, Intel and AMD used to have processors with a single core. This essentially meant that the processor would behave like a single processor allowing only sequential operations on the CPU.This was limiting the operations of heavy processor intensive applications. This is where the concept of hyper-threading came into being.

Intel released its first Pentium 4 processor with hyper-threading in 2002. Hyper-threading is a process of creating two logical processors on one physical processor. This is all done on a software level. These changes are visible to the Operating System which can make use of hyper-threading.

In 2005, AMD released its first dual core processor which included two physical cores on one CPU. Since these cores were implemented on a hardware level, it offered better performance than Intel’s hyper-threading model.

After AMD’s success of implementing physical cores, Intel introduced the dual core model first which was not efficient. Core Duo model was introduced specifically for laptops but it was also implemented on Desktop computers as well due to its efficiency and speed.

After the release of Core 2 Duo processors, both Intel and AMD are quickly introducing processors with more and more cores installed on the same physical processors. The main benefit of this is that the processor slot on each computer will essentially remain one. Having more than one core means that the Operating System will have a feel of more physical processors as opposed to a single one. This will increase the efficiency of all open applications.

The latest microarchitecture of AMD is called AMD Bulldozer Family 15th microarchitecture. This includes 8 physical cores on each processor. Each of these physical cores can have two logical cores which makes the total number of cores available to the Operating System to 16.

The latest microarchitecture of Intel is called Sandy Bridge which was released at the start of 2011. It was implemented in Core i7 series of computers, laptops and mobile devices. It also has 8 physical cores and can be extended up to 16 logical cores through hyper-threading which was re-introduced in this model.

The Sandy bridge and Ivy bridge are the same microarchitecture but the difference between the two is that Sandy bridge uses 32 nanometer manufacturing process while Ivy bridge uses 22 nanometer process. The main benefit of these microarchitectures is that they make the L2 and L3 cache available for all cores at the same time.

I hope, by now, you have understood the concept of physical socket, physical core and a logical core/processor. Before we end this article, let us go through the summary definition of each one of them.

Physical socket: It is the actual spot on which processor is fixed on the motherboard.

Physical core: It is the division of the actual processor on a hardware level.

Logical processor: It is the division of a physical core by using hyper-thread or other techniques.

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