Socket A (also known as Socket 462) is a zero insertion force pin grid array (PGA) CPU socket used for AMD processors ranging from the Athlon Thunderbird to the Athlon XP/MP 3200+, and AMD budget processors including the Duron and Sempron. Socket A also supports AMD Geode NX embedded processors (derived from the Mobile Athlon XP). The socket is a zero insertion force pin grid array type with 462 pins (nine pins are blocked in the socket to prevent accidental insertion of Socket 370 CPUs, hence the number 462). The front-side bus frequencies supported for the AMD Athlon XP and Sempron are 133 MHz, 166 MHz, and 200 MHz. Socket A supports 32-bit CPUs only.