AFAIK, recognition of the RAM speed is automatic, so a 2-2-2 RAM stick should be used as one, unless there is slower memory present, which would reduce the speed to a slower value.
(However, my cube would not recognize my 2-2-2 stick as such, it is used as a 3-2-2, for whatever reason. The stick is branded Infineon RAM and states 2-2-2 on the label. But there might be another reason for that which I have no clue of...)