I have that board too but I don't have a problem going up to 1.9... I'm not sure but when i used a 700E on it the voltage would go to 1.9 and on a 800E it would go to 1.95... maybe there's a cap that prevents you from going too far over the manufacturer's OEM setting..
I'm not sure so don't quote me... I'm too lazy to swap the chips back just to see, sorry. =P