There is a performance difference crazybus, your processor doesn't just instantaneously go from 2.4Ghz to 4Ghz. It goes from .9V x6 multiplier to 1.3V (or whatever you have it set to) x9 multiplier. It then takes whatever time for that to equate to the boost in power. When I was running benchmark tests with speedstep on my CPU was constantly going from 2.4Ghz to 4Ghz off and on, even though there were programs actively happening. It was like it wanted to save every bit of power possible which is good, but from a gaming performance standpoint, how much am I losing in it revving up and down? What are the disadvantages to those of us who OC to this kind of throttling and is it really reducing the voltage if we have the voltage actually preset in our BIOS for our overclock?
I don't think I have ever seem an indepth review of SpeedStep and CPU throttling, therefore I am not really convinced given what I know about EE that it won't hurt my performance. Do I notice it hurting performance in games and applications, I don't know, it seems a little slower to react sometimes. I feel my 3DSMark scores were a little lower. When I do OCing and benching, I turn it off. For everyday use, I leave it on.
As for dynamic OCing, I don't know that there is really a big market for that. I think a lot of us just do the OC ourselves and feel better about it that way, but that is just my opinion.