Socket 940 is a 940-pin socket for 64-bit AMD Opteron server processors and AMD Athlon 64 FX consumer processors.

It was one of the first sockets designed for AMD's AMD64 range of processors.

This socket is entirely square in shape and pins are arranged in a grid with the exception of four key pins used to align the processor and the corners.

Microprocessors designed for this socket were intended to be used in a server platform, and as such provide additional features to provide additional robustness.

[1] While the more recent 940-pin socket AM2 is visually similar to this one, the two are electrically incompatible due to the integrated memory controller.