Application.targetFrameRate... no effect at all

So I set Application.targetFrameRate to 20 (to test if it works), it does not set anything (in standalone or web player) but when I Debug.Log(Application.targetFrameRate), it returns 20.

Why.

I’ve been using it on iOS recently on Unity 3.5.5 Pro and there it definately did change, checked with a FPS counter …
i’ve been using values between 30 and 60, though.