What CPU you running? Most of the CPU's then only support 1066 & 1333 memory. Yes it says that it can run the 2133 but you have to OC to get it to run at 2133. If you put in 1066, 1333 it will really run faster then the 2133. But I'm done going there sorry.
I know what it says that it will run DDR3 2133/1866/1600/1333/1066 MHz memory modules. But what really should say is Support for DDR3 2133(oc) /1866(oc) /1600(oc) /1333/1066 MHz memory modules. To get it to work you need to OC your CPU.