Well there's a tiny, tiny difference. I guess it's c6/7 that's keeping the consumption low?
800MHz at idle
Gadget Package Pwr = 8.5w
Killawatt reading total system = 57w
4300MHz at idle
Gadget Package Pwr = 8.7w
Killawatt reading total system = 57w
Same settings between the two. I just opened the power options and set minimum processor state to 100%. The Intel gadget and other programs such as hwmonitor shows all cores of the processor staying at 4.3GHz when I do this.
I have no idea why yours is like that. I just tested mine - which is a Core i7 4770K with all 4 cores overclocked to 4.3GHz and I have an ATI 7970 video card, 1TB SSD, and a whole lot of fans.
800MHz at idle
Gadget Package Pwr = 15.2w
Killawatt reading total system = 71w
4300MHz at idle
Gadget Package Pwr = 26.3w
Killawatt reading total system = 83w
To get it to idle at 4300MHz, I went to Windows -> Control Panel -> Power Options and chose "High Performance". To get it to idle at 800MHz, I chose "Balanced".
You might say "hey, 26.3-15.2 isn't equal to 83-71" and I can't explain that. I just read the numbers. But I'd guess my Killawatt rounds the numbers and that's why.
But I will say that a ~11W delta is about what I would have expected. Maybe even a little better than I would have expected.