Socket 603 is a motherboard socket for Intel's Xeon

Xeon

The Xeon is a brand of multiprocessing- or multi-socket-capable x86 microprocessors from Intel Corporation targeted at the non-consumer server, workstation and embedded system markets.-Overview:...

 processor.

Technical specifications

Socket 603 was designed by Intel as a zero insertion force socket intended for workstations and server platforms. It contains 603 contacts arrayed in a grid about the center of the socket, each contact has a 1.27mm pitch with regular pin array, to mate with a 603-pin processor package. Intel's design notes distinguish Socket 603 from Socket 604 as low cost, low risk, robust, high volume manufacturable, and multi-sourceable.

All Socket 603 processors utilize a bus speed of 400 MHz and were manufactured in either a 180 nm process, or 130 nm process. Socket 603 processors can be inserted into Socket 604

Socket 604

Socket 604 is a 604 pin microprocessor socket designed to interface an Intel's Xeon processor to the rest of the computer. It provides both an electrical interface as well as physical support. This socket is designed to support a heatsink....

designed motherboards, but Socket 604 processors cannot be inserted into Socket 603 designed motherboards due to one additional pin being present. Socket 603 processors range from 1.4 GHz to 3 GHz.

No Socket 604 processors are produced with Intel's "MP" designation, while some Socket 603 processors have receive the "MP" designation. The "MP" next to the processors speed is the inclusion of an L3 cache to boost performance in multi-processor computers ("multi-processor" meaning they have more than 2 CPUs), however, some socket 604 processors are now being manufactured with the addition of an L3 cache up to 16 MB.