anywho, i tried running df with 2400mhz ram, with no visible changes. guess df is only cpu dependant
edit: seems i was too fast to judge. being a bad overclocker that i am, it looks like as the game went on the fps went from 40 to 80s+ the longer the game is left running. i suspect it adds up voltage over time to increase performance, although its just a thought
It's very unlikely that you will see voltage spikes in the voltage given to the memory , basically if you use SPD or XML profile the memory should be ready to go at that velocity.
However if it's not made for 2400Mhz , then you will have to manually adjust both latencies and voltage to a set number in order to keep the memory stable and error free.
A cpu however might need a different approach when you overclock it , but now a days the software that comes with Asus and other kinds of motherboards are pretty easy to use and as long as you go slow with the overclock you will probably get a nice stable overclock without too much hazzle.
Personally I never add too much Voltage , in fact for cpu's I prefer to max overclock with a lower voltage than what the cpu is shipped with , then run several prime95 tests and other test to stress test the cpu to the max and look for discrepancies there.
Why do that? Well , once you get your cpu up to a pretty nice and stable speed you will be able to have more dwarves without seeing the dreaded fps loss in the early days...