Is there any proof?
Is there any definitive proof that the KT400 WILL NOT support DDR400? Or do the KT400 mobos seen so far simply not support it?
IIRC I read somewhere (maybe Anandtech) there are no DDR400-capable sticks out there yet, so there's no way to find out if the KT400 supports DDR400 until there are.
Frankly I'd take this with a grain of salt until a reference board is reviewed with DDR400 in its memory slots and the board starts crashing with a 200MHz memory bus.