Hmm..I don't recall my board having such a jumper. Also, I don't have the ability to change the fsb/memory settings, or whatever it is. It only gives me the 1:1 option for the memory speed... I don't recall seeing any updated bios for the P4B266-C the last time I looked ovef ASUSs website either, and the P4B266 has the option to change that aswell.
It would be nice if somebody could clarify this, and to be able to tell me which rev to get and/or which board to get. I'm mainly wanting that jumper for higher voltages.