My rig: 5 xfx 470, core 1100, memory 1975, 141mhs and 685 watts in the wall.

How you did the lower the voltage on xfx ?
I can not control the voltage on my xfx`s i did try with wattol, afterburner, trixx... no one work for me

XFX cards are fucking terrible, and don't use the usual voltage controllers.
These cards are actualy quite good price/performance/awalability ratio
But is there ANY way to change voltage? Even bios or other ways?
I think i can experiment now with bios to see if it works, but i want to see some other people experience first.
Technically, yes, but it's not going to work the normal way. I2C is probably the only way.