If your motherboard says 2400MHz or 2133MHz RAM only then the RAM run at 2133MHz automatically when you first install it. You may be able to use XMP to get it to run at 2400MHz. It may be stable at that speed, it may not. You won't see a performance difference if you are using a Intel G4600 at 2133MHz which is the lowest default DDR4 RAM speed. Either way you should be fine.