Re: Speedstep ?
C1E turns down the cpu multiplier and voltage when the cpu is in it's halt state doing virtually nothing. Since this only happens when the cpu is at idle or a low demand state (like right now it is in effect while I just have IE8 open) it won't really affect any performance in programs such as games.
Example: You are playing a game so the clock speeds and voltage stay at max levels until you quit the game and the computer is idling, it then drops the CPU speed and voltage while idling.
EIST adjusts CPU clock speed and voltage according to the demand being placed on the system. So if you are using a program that isn't using the CPU 100% it may drop the speed and voltage down.
Example: You are playing a game that isn't taxing the CPU 100% so EIST will adjust the CPU speed and voltage to try and match the demand being placed on the system such as lowering the CPU speed and voltage 25% or something while in the game.
I do not like to use EIST because when I am using the computer to play a game or edit video or whatever I want it always using the CPU at max speed and not trying to figure out if it should drop the speed here and there.