The GA-G31M-S2L apparently has a memory multiplier that is locked at a minimum of 2.66, which is stupid.
No. What happens is that the motherboard reads the little SPD chip on the RAM sticks. What you need to do is go into the BIOS and somewhere down where the memory settings start, change the SPD setting from AUTO to manual. When you select MANUAL, you will be able to select from a group of multipliers. Choose the 2.0 setting. You will then see the memory clock
setting change to 2 times the FSB.
At that point, CPUZ will show the memory frequency
to be equal to the FSB frequency of 333 MHz.