Feed the maximum VMCH you have so to go higher....Apparently if you haven't done the VMCH "boost mod", giving 2Volts in bios, it's about 1.83 - 1.87V real....so it's OK....

I also want to add that EVEN with 1.2VFSB, MOST (if not all) of the CPUs could do over 400MHz for sure......Just pop up more VMCH .....and a fan over Northbridge will be helpfull....