Despite many rumors that Intel plans to launch X48 in November, according to current plans it won't happen until January, at the earliest.
The current roadmap shows the X48 chipset ready for Q1 2008, to meet the launch schedule for the QX9770 FSB 1,600MHz CPU. The whole point of the new chipset is official support for 1,600MHz FSB, and Intel plans to stick with DDR3 1,333MHz support, as Jedec doesn’t recognize 1,600MHz as a standard. Obviously, X48 will let you drive your memory to 2,000MHz or beyond, but not officially. Intel will call this overclocking.
The new chipset also supports PCIe 2.0, Intel’s XMP, Extreme Memory Profiles for DDR3, but this is something that you will also see with the X38 chipset. You can relax if you don’t want the 1,600MHz FSB, you can forget about X48, or you can always wait for it to arrive in January 2008. The choice is yours.