Ok thanks for the infos! At the light of what you say, I'll keep my CPU at 4,4 with the set voltage. Temperature is well under controll and from what I know of Haswell, it's a respectable score. I don't want to bench for the fun of it and XTU showed that the CPU is stable after hours of 100% load so it did what I needed.
I don't know what MOBO you have.
But if you have an Asus MOBO, switch to Adaptive voltage from Manual.
I don't know what is the equivalent of Adaptive on other manufacturers, but I think everyone has one.
If you leave the voltage at Manual, your CPU will be fed the same voltage regardless of the clocks.
It will be the same 1.29V for 800Mhz & 4400Mhz.
This is not ideal in neither in the term of power consumption nor temperatures.
Adaptive allows the voltage to scale with clocks.
Manual is only ideal for stress testing.
Adaptive means stocks volts plus a bit more offset to account for the higher clocks.