The Socket 604 utilized the pin grid array and was used by Intel for the Xeon processors. It is very similar to Socket 603, in that it has 603 electrical contacts (pins), but it also has an additional dummy pin, for a total of 604 pins. Socket 603 processors could be used with a Socket 604 motherboard, but the Socket 604 processor could not be used with a Socket 603 motherboard due to having the one additional pin. Socket 604 was a more expensive processor, being able to support a wider range of CPU speeds and front-side bus speeds, as well as being used by multiple Intel Xeon chipsets.
Socket 604 supported front-side bus speeds of 400, 533, 667, 800, and 1066 MHz, with CPU speeds ranging from 1.6 GHz to 3.8 GHz. It supported multiple Intel Xeon chipsets, including E7500, E7501, E7205, E7320, E7520, and E7525. It also supported Intel 7300, which was for the "Xeon Tigerton" Core series and "Xeon Dunnington" Core 2 series processors. One additional feature of Socket 604 was the manufacturing process used to design the processors. Four options were available, being 130 nm process, 90 nm process, 65 nm process, and 45 nm process.