SW vs HW acceleration, against cpu brands

I think my old problems may not be relevant anymore. (however I will test) so let me ask my main questions again, to get back on track.

What does HW acceleration do?
Can I run an AMD Chip in HW acc OFF mode the same as an i7 chip?
Can we expand on the what with respect to the hardware AMD vs intel (QuickSync)

In the meantime I am testing HW mode on on my intel chip.

my next investigation will be what happens when I add my nVidia1070 gpu to the HTC.