Well the problem,mainly the solution do tell that this is a bios problem...However,it depends on the divider you are using to get that frequency over 1100 mhz,for example,my memory can do 4-4-4 at 600 mhz,using 4:5 divider,but they cannot do it still at 600 mhz,but using 2:3 divider,so this is also a matter.