[Tristan Lall]

In fact the 754 is an older AMD socket, the 939 is the current one, and 940 is also a current AMD socket, but used on the (more expensive, but similar) Opteron processors. These are Zero Insertion Force (ZIF) sockets. Lift the lever, drop the processor in, close the lever; don't push down with any appreciable force. The socket will be labeled with the type, but it may be hard to read, or obscured by other components. Look closely. Alternatively, pinouts are available from AMD.

Socket 775 is an Intel socket, for the newer Pentiums and Celerons; it's actually a Land Grid Array (LGA) socket, where the pins are on the motherboard, and the processor has pads on it—it makes the CPU cheaper and less prone to damage.