Socket P is a central processing unit (CPU) socket that semiconductor company Intel Corporation debuted on 9 May 2007 for some of its mobile processors. These are CPUs that Intel designs specifically for application on laptop, or notebook, personal computers (PCs). Intel designated it as the successor to Socket M. The main function of the Socket P, like other processor sockets, is to serve as a spot on the computer's motherboard where it can be plugged in for stability and data transfer.
Each Socket P has 478 pin holes, which it uses for accommodating the pins of the CPU. Intel arranges these pin holes in neat rows at the sides of the socket's square-shaped structure. This arrangement is known as a pin grid array (PGA). Socket P's predecessor, Socket M, also has 478 pin holes, so the former also goes by the Micro FCPGA-478 and the latter by mPGA478MT for further differentiation.
More specifically, Socket P uses a PGA variant called flip-chip pin grid array (FCPGA), which involves the back of the CPU's die—the wafer of semiconductor material that contains its cores, or processing units—facing upward. The FCPGA design of Socket P permits users to place a heatsink on the die, which decreases the processor's heat and consequently increases its energy efficiency. It is a form factor that Intel introduced with the debut of Socket 370 in 1999 for some of its low-end Celeron and then-flagship Pentium III computer chips.
Intel primarily uses Socket P for CPUs from the Intel Core 2 brand, which appeared in 2006 to replace the Pentium as the company's premier family of computer chips. More specifically, the socket is compatible with the T5xx0, T6xx0, T7xx0, T8x00 and T9xx0 series of the Core 2 Duo Mobile—Core 2 laptop PC chips with two cores—and the Q9x00 series of the Core 2 Quad Mobile—Core 2 laptop PC chips with four cores. The Pentium, by now demoted to mid-range status, and the Mobile Celeron, were not left out, though. Intel extended compatibility to the Pentium's dual-core T23x0, T2410, T3x00, T4x00 series, as well as all Celeron M processors. The accommodated data transfer speeds are 400, 533, 667, 800 and 1,066 megahertz (MHz), or million transfers per second (MT/s).
Socket M is also compatible with some of the members of the Intel Core 2 Duo family, particularly of the T5xx0 and T7xx0 series. Moreover, users can physically fit Socket P or Socket M into Socket 479, which preceded them both in 2003. Neither socket, however, shares electrical compatibility with Socket 479.