Intel Sockets: LGA 775, LGA 1156, LGA 1366, And LGA 1155

Socket LGA 775

Socket LGA 775 (also called Socket T) is used by the Core 2 Duo/Quad processors, the most recent versions of the Intel Pentium 4 Prescott processor and the Pentium D and Pentium Extreme Edition processors. Some versions of the Celeron and Celeron D also use Socket LGA 775. Socket LGA 775, unlike earlier Intel processor sockets, uses a land grid array format, so the pins are on the socket, rather than the processor.
LGA uses gold pads (called lands) on the bottom of the processor to replace the pins used in PGA packages. It allows for much greater clamping forces via a load plate with a locking lever, with greater stability and improved thermal transfer (better cooling). The first LGA processors were the Pentium II and Celeron processors in 1997; in those processors, an LGA chip was soldered on the Slot-1 cartridge. LGA is a recycled version of what was previously called leadless chip carrier (LCC) packaging. This was used way back on the 286 processor in 1984, and it had gold lands around the edge only. (There were far fewer pins back then.) In other ways, LGA is simply a modified version of ball grid array (BGA), with gold lands replacing the solder balls, making it more suitable for socketed (rather than soldered) applications. Socket LGA 775 is shown in the figure below.



http://www.tomshardware.com/reviews/processors-cpu-apu-features-upgrade,3569-10.html