I'm big AMD supporter, by major factor because of their opensource policy. However no-matter which processor comparison test I look, AMD systems are always draining a lot of power.

For desktop - about 15-20 Watts more in idle, and about 20-40 Watts more under load.

For example
, lets us take Athlon II X4 630 and Intel core i5-750.
A almost cache-less 630 consumes way more juice than 750, whilst also performing worser. In my country juice is not cheap and eventually, when using the mentioned processors in long 2-3 year window, renders 750 cheaper in total cost than athlon II x4.

I found a way to undervolt my athlon II x4 630, from ridiculously high 1.4 volt Vcore (only found on full-blown Phenom II) to 1.25v, leading to consumption drop of around 25 watts in load (120w instead of 145w) and 10 in idle(100w->90w), with zero impact on stability. The logic of my mainboard allowed to reduce via percentage, not value, so that reduction scales down very well when CPU is going into cool'n'quiet mode.

Prior to my switch from intel e5300/gf9800gt to full amd system, I had an opportunity to play with intels Speedstep, which basically reduced CPU multiplier to 6. Both cores still run @ 1.2 Ghz, where on Athlon II x4 due to CoolnQuiet(and on-demand governor) all four run at just 0,8Mhz with Vcore reduced too.

My main questions are:

1) Why is AMD K10 draining so much more in performance per watt than Core or even Core2Duo? Whats the reason behind so much difference?
2) Will there be any change with Bulldozer?
3) Why is Athlon II X4 spec'ed at 1.4v when it runs with 1.25v (or even 1.20v if u do internet search) just fine?

Please no intel fanboyism. Ty.