I have one corsair vengeance 1600mhz cl10 and put it together with 1333mhz zeppelin cl9. After a few days everything is stable and I see gains from dual channel performance.
Set both sticks to 1333mhz , in most cases should work fine ,
I have a similar setup ,what I did was downclock the 1600 to 1333
I don't know if you can see the picture, but both modules set automatically to 1600 cl11 and work in dual channel mode. So do i still need to change to 1333 ?