u have a nice Q6600 -atlxkevinx- i have one with the exact same vid .. on water it does 425x9 @1.36v .. although on my tr ultra it heats up pretty bad .. maybe its teh IX38 quad gt that heats it up that much

and yes u must up the voltage for higher clocks ..

mine will do 3.6 with 1.25-1.26.... dont think ull be needing water at this speed.. just a good aircooler..