Socket 479

Socket 479 (mPGA479M) is the CPU socket for the Intel Pentium M and Celeron M mobile processors normally used in laptops, but has also been used with Tualatin-M Pentium III processors. The official naming by Intel is μFCPGA and μPGA479M. There exist multiple electrically incompatible, but mechanically compatible processor families that are available in PGA packages using this socket or variants thereof: Socket 478 for Pentium 4 and Celeron series desktop CPUs; Socket 479 for Pentium III-M (released in 2001); Socket 479 for Pentium M and Celeron M 3xx (this was the most common version of the socket, and was released in 2003); Socket M for Intel Core, Core 2 and Celeron M 4xx and 5xx processors; and Socket P for Core 2 processors. Even the Intel's CPU specifications seem to be not clear enough on the distinction and instead use the package/socket designations PGA478 or PPGA478 for more than 1 of the above sockets. Perhaps adding yet more confusion, some of the PGA-based CPUs above are also available in a BGA (or more precisely, μBGA or even μFCBGA) package which has all of the 479 contacts (balls) populated. For these CPU variants, the Intel's CPU specifications use the designations BGA479, PBGA479 or H-PBGA479. It should be however pointed out that these designations denote rather the CPU package itself and not the socket, which the BGA variants do not use at all (they are intended to be directly soldered to the mainboard, e.g. in an embedded system). The non-BGA counterparts of these CPUs use any one of the above mentioned sockets, not only the Socket 479. Socket 479 has 479 pin holes. Pentium M processors in PGA package have 479 pins that plug into this zero insertion force socket. Only 478 pins are electrically connected (B2 is reserved and "depopulated on the Micro-FCPGA package"). Although electrically and mechanically similar, Socket 478 has one pin less, making it impossible to use a Pentium M processor in a 478 board. For this reason manufacturers like Asus have made drop-in boards (e.g.