Drop the the multi to 7 and you can put the FSB up to 450 that might work but you will have to raise the vcore to about 1.5v and that will get you to 3.15Ghz or you could just try 8 x 400 for 3.2Ghz. 437.5FSB x 8 for 3.5Ghz Might have some difficulty getting much higher then that I think
I was just reading some info on this board and they mentioned the CPU you have at 512FSB
Motherboards - nForceĀ® 7 series - nForceĀ® 780
512 x 8 = 4.096Ghz SWEET!!