socket 423 - pentium 3
socket 478 - pentium 4 (willamette and northwood)
That is wrong.
Socket 423 was the early P4 socket, it only goes up to 2gigs and is only for willamettes.
Socket 478 is for newer P4 chips some older willamettes are supported all northwoods are supported. Northwoods start at 1.6Ghz and up.
Socket 370 for the Cu P3s and i think some Katmai.
My opinion is stay away from the 423.