What Is Socket 604?

Socket 604 is a central processing unit (CPU) socket that Intel Corporation released in 2002 for its Xeon processor brand. The CPU socket was designed to electrically connect the CPU to the motherboard for data transfer. It also provides physical support and acts as a protective interface so that users have a smaller chance of damaging the CPU when removing or inserting it.

Intel named the Socket 604 after the number of pin holes it possesses. The contacts, however, consist of 603 active ones and one dummy pin. These contacts, which support the processor and have a 0.05-inch (1.27-millimeter) pin pitch, are arranged in orderly rows along the socket’s square-shaped structure. Thus, it adheres to the pin grid array (PGA) form factor. Intel gives it a zero insertion force feature so that no force is necessary for removing and inserting the chip.

The only Intel CPU brand compatible with the Socket 604 is the Intel Xeon. Debuting in 1998, the Xeon was designed for server and workstation motherboards, as well as embedded systems. Not all Xeon CPUs are compatible with the socket, however. The chip fitted on the socket must have a data transfer speed of 400, 533, 667, 800 or 1,066 megahertz (MHz), which translates into 400 million, 533 million, 667 million, 800 million and 1.06 billion transfers per second.

Also, the Socket 604 processors were manufactured using the 130, 90, 65 or 45 nanometer manufacturing process, which determined their size. The smaller the number of the lithographic node, the smaller the CPU is. The Intel E7500, E750, E7205, E7320, E7520 and E7525 are the Intel Xeon chip sets compatible with the Socket 604.

The 603 active contacts rather than the full 604 would suggest that Socket 604-compatible Xeon chips can work on the Socket 603, which was released in 2001 and is the immediate predecessor of Socket 604. They cannot work, though, because the processors still have that extra 604th pin. Socket 603-compatible Xeon chips, however, can go on the Socket 604, since they have no need for the dummy pin.

Although the land grid array (LGA) 775, or Socket T, seemed to threaten Socket 604’s Xeon primacy with its 2004 debut, it was only compatible with the 400-MHz Xeon CPUs. Moreover, it actually had a lower data transfer speed requirement with its 133-to-400-MHz range. Subsequent sockets, however, such as Socket M and LGA771/Socket J in 2006, LGA 1366/Socket B in 2008, LGA 1156/Socket H in 2009 and LGA 1567 in 2010, superseded the Socket 604.