okay.if you use the 5:6 divider 333strap 2.40B it will give you ddr-960.heres the math for 5:6 divider
400fsb x 6 = 2400 then divide by 5 = 480 x 2 = 960Mhz. thats how the dividers work.
heres the 4:5 divider 400fsb x 5 = 2000 divide by 4 = 500 x 2 = 1000Mhz
hope this helps.