Heres my implementation of the 1668. Works a charm!
I hooked up the SMBus on the backside of the mobo, on the RAM socket solder points. I also made a connection on a RAMstick... But the backside of the mobo was far more easy to solder and that is tha connection I use
EDIT: The Mobo is an Epox 8rda+ but any mobo with DDR should have the same pin configuration