For what MB as the frequency may be limited by the MB capabilities?
For an example, you can get
Corsair Dominators GT 2625MHz or slightly more conventionally
Corsair Dominators GT 2000MHz but some motherboards wouldn't be able to run memory at this spec...
In reality the
XMS3 is perfect for everyday use (gaming apps etc) and you wouldn't notice any real gains betwen the 2 specs in general usage.