I will give you this though... 300 amps at .6v... maybe now you understand the problem...
300amps @ 0.6v? So that's 180 watts if I remember my maths correctly...
180w for what though? Per chip? Per device?
I think that the Habanero is running 600+ watts through a single board. 4 6 pin power plugs.
It gets pretty dang hot.
Just as a comparison.