How microprocessors work

Modern processors are encapsulated onto a single chip (miniaturized electronic circuit made of silicon) where communication is provided through the pins: 

These pins are connected via sockets built into the motherboard, and the number of pins of the processor, with the layout (design) of the pins determines which processor the motherboard will support. Most processors have 1155 sockets however the newest high end processors such as the i7 900 series have 1366.

There are standards for the layout and pinout of the processor and socket, the most used are: 

PGA (pin grid array) 


In the standard pin PGA processor presents on the back of the processor. 

 

Some examples of manufacturers, processors and standard PGA sockets: 

AMD: 

Socket 939 
AMD Athlon 64 (3000 + - 4000 +) 
AMD Athlon 64 FX (51 - 60) 
AMD Athlon 64 X2 (3600 + - 4800 +) 
3xxx + Sempron.