More commonly called LGA775, Socket T is an Intel CPU socket (also called processor socket) that uses Land Grid Array (LGA). Socket T supports Pentium 4, Celeron, Core 2 and Quad Xeon. Using the word socket in connection with LGA775 is somewhat misleading. Traditionally CPU sockets contain holes that pin on the underside of the CPU it contacts with. However, with the LGA775 there are no holes, but instead 775 pins protrude from the CPU socket that make contact with points on the underside of the CPU.
