You got a crap mobo my friend
actually from what I am reading the FSB can go up to 409... Maybe that board just cant handle the Quad cores power draws? Try to get the Vcore AFTER Vdrop to be 1.35-1.4
We believe this is near the limit of the CPU/chipset combination. Vdroop was terrible on this board during overclocking with an average drop of .06 ~.09V during load testing.
ok here let me help you figure this out. We are going to take the CPU and memory out of the picture to first find out what your FSB can do. Set your CPU multiplier to 6X and memory divider as low as high as it will go. Raise the FSB in 10MHz steps and reboot each time. Once its no longer stable we will know what the chipset can do. After that it will be up to your CPU and motherboards voltage regulation...