|It's which CPUs, not what CPUs. Your board is pretty ancient. I don't know which CPU you currently have, but you definitely need a RAM upgrade.|
According to the FIC site, the CPU support depends on which board PCB version you have & which BIOS version. The AZ11EA supports the older Athlon Thunderbird & Duron Spitfire, but also the Athlon XP Palomino & Duron Morgan with the proper PCB & BIOS. The Athlon XP Thoroughbred, Thorton & Barton are NOT supported.
CPU support list