I could pull that down to around 5A with -100mV on the core clock, also stock clocks! Not bad at all! (Afterburner). "1100watt"
So with only doing that i would win 400 watt and some serious temperature changes.
Well, that wasn't enough for me :p
So i started messing around with the bios "rom".
I managed to modify the bios to set the stock vddc to -100mV (Afterburner's maximum negative offset is -100mV).
I also managed to modify the MVDDC, "Memory Voltage", also to -100mV (can't even do that in afterburner :p).
Ran another test with settings in afterburner at stock, didn't change a thing. And guess what?
Yeah, power went down to 4.85A

"1055watt" another 45watt win. (not much but it's something!)
Enjoy!
Thanks for the good efforts.
So the memory consumes very little energy. With -100mV, power drops from 1100 to 1055W.