slaman,
the 133:100 ratio is for the back side ( memory ) bus to run at 133mhz and the front side bus to be run at 100mhz.
the memory bus isn't allowed to run below the front side bus. it can only run synchronously ( aka 3:3, 100:100, etc. ) or asynchronously ( aka 4:3, 133:100, etc. ) which...