Got Gigabyte HD3850 to mod- it has non-reference pcb with Nexsen PWM controllers on it.
Card has Zalman cooler and blue pcb, but I think same mods can be used for other cards with same PWM chip.
Vgu mods- I measured 10K resistance between GND and FB pin.
This is without mods!
Red line is connected to FB pin and any point of it can be used for "fooling" feedback voltage to chip.


Vmem mods- same story.


Actual mods on extra pcb:

and schematic diagram:

Voltage monitoring poins are knows already I think.
Mods working fine, Vgpu is limited at ca.1,75V with extra resistance on Vgpu, if you need more, use resistor with lower resistance.