socket 423 vs 478

What is the difference between socket 423 and socket 478...Ben searching but no luck so far...anyone????

Socket 423 CPUs are the first (and now basically obsolete) P-4's introduced (has 423 pins). The socket 478 CPUs are the newer P-4's (has 478 pins). The older Willy P-4's (256k cache) are available in both flavors. The newer Northwood P-4's (512k cache) are only available in socket 478. A socket 423 CPU will only fit in a socket 423 motherboard and a socket 478 CPU will only fit in a socket 478 motherboard. They are not interchangeable. If you're buying a new P-4 system, avoid the socket 423 like the plague because you will not be able to upgrade the CPU later on.

I also believe the 423 will only run RAMBUS memory, while the 478 will run SDRAM or DDR.

423 runs, sdram, ddr, rdram.