From what I've read is that the X48 chipset is really only cherry picked X38's that Intel validates to run at 1600 FSB. Much like speed binning CPU's from a CPU family such as Allendale (E6300, E6400), Conroe (E6600, E6700), Kentsfield, etc. No other features have been added to the chipset other than the official support for 1600 FSB. So if you plan on running a QX9770 or if Intel plans on releasing mainstream CPU's with FSB's of 1600 and you want a chipset that "officially" supports that FSB, get the X48, otherwise get the X38. Of course when I say "officially", I mean that in all likelihood, you would be able to run a X38 motherboard at a FSB of 1600 without much problem, heck most P965's have no problem running with an FSB of 1600 or higher.