5850 voltage control

[SMOKEU]

My XFX 5850 doesn't seem to have any voltage control. I tried to adjust the voltage with Afterburner and Trixx, but the voltage is locked. I can easily change the voltage on my 6950. Would voltage control be available if I make a new BIOS with Radeon BIOS editor or if I downloaded a new BIOS? My card is this one here http://xfxforce.com/en-us/products/g...ries/5850.aspx