DDR2 with DDR 400

can a motherboard designated as DDR2 667 use regular DDR 400? I am trying to piece an old pc together to keep it running for a little while longer, and the mobo that I have is DDR 400 478 socket. The board is dying, but I dont want to buy all new pc parts, I just want to replace the mobo, but choices are slim at newegg for a 478 socket p4 board. So if DDR 400 will work just fine in it, that would be just fine with me :)

No, they are physically different and can't interchange.

Sorry.

hmm, ok. Thanks, I guess I will keep looking for a compatable board. Thanks again :)

In addition, if you don't get a Socket 478, you won't be able to use your P4 (I'm assuming that's what you have).