PGA, SPGA with 321 pins, and PGA, SPGA, and FC-PGA with 296 pins.
AMD K5 and K6, Cyrix 6x86, Pentium, and Pentium MMX.
First socket to support dual voltage inputs, which support the various core and I/O voltages introduced with the Pentium MMX processors. Socket 7 has one more hole than Socket 5, but is not electrically connected. It simply prevents a new CPU frm being plugged into a Socket 5 socket.