I don't know where you think you got that information, but I haven't even heard of an SiS 663 chipset...I'm pretty sure there's no such thing.

I mispoke anyway; it's the 963 southbridge that doesn't have SATA, which the P4S61 is equipped with. 964L has SATA.

I've handled a P4S61 anyway; they were common cheap solutions, like the P4i65GV.