CPU (Central Processing Unit)

PGA

reffered as pin grid array in which pins of CPU are lined up in a straight format.

SPGA

referred as staggered pin grid array. in which pins of CPU are arranged staggered format.

LGA

reffered to as Land Grid Array in which pins are available within inside the socket but not in the CPU in other words in line grid array, in CPU ther are no pinsbut insteadpins areattached with in a socket which contact with with the CPU. for e.g. LGA775 socket(no pins on cpu)
has better cooling system.

1. better contact and better locking(climbing).
2. LGA1155:
3. Letest generation I socket, also reffered as sandy bridge,
4. Turbo boost overclocking.
5. More resent than LGA 1156 socket.
6. LGA1156:
7. ability to north bridge
8. Doul channel DDR3
9. optional integreted graphics
10. PCI express
11. LGA1366:
12. hi end core i series socket
13. integreted tiple channal
14. memmory controller
15. external control bridge(HUB)

Upgrading CPU:

1. need to check its core suppert
2. check multiprocessor supports or not
3. check on the internet for the necessary compability
4. check the bus speed
5. compare the price