I will never go to 1.2v, I am not after a extreme overclock, I want sane temperatures. IF I only managed to get 4.0 with this overclock then its probably where I stay. I just got lucky, I may try 4.4 (but only at the same voltage).
Also adaptive voltage keeps the same voltage when the cpu is not in turbo mode, so eg. if the pc is idle for 10 hours, then those 10 hours its the same as stock clocks/voltages, it will idle at 800mhz and use about 0.1v. Adaptive voltage is a new thing with haswell.