How to adjust the voltage of a Powercolor 5850 PCS+??

[Fitzroy]

I have purchased and mounted a powercolor hd 5850 pcs+ after changing the same with my 4650. It looks great card stays fine and seems very cool (have only moved up to 58C with furmark) but I am unable to get this past 875/1150 (gpu/mem clocks).
I initially tried to go with the MSI afterburner , configured the cfg and enabled unofficial clocking and switched on the voltage control and monitoring but I still getting unable to change the voltage via afterburner so it seems unstable whenever I push it past 900/1150.

[Pugsly]

I was so scared to perform the same at primary stage but when my roommate have a lot of knowledge about the programming and was there supporting me with the ms-dos, In the last stage, I have flashed my powercolor BIOS to the ASUS unlocked BIOS (thanks to aquax and DesertRat for their support) and launched the beast..

[Regina]

Have you moved through only OC with CCC? Damn it all...seems as I should be returning mine. This is an Asus 5850, but it would not OC worth a darn. A big 775 core and 1050 on the memory. I was moving to be going through the trial to increase the voltages and a little to find out if it would be helpful for you all, but if you got that far by just working with the CCC then I should mostly just forget the same.

[Fitzroy]

First of all ,I would say thanks to all of you for the reply and suggestion regarding the same but just need to be sure as I have stated in the first post, I have flashed both the asus and msi bios on my card.

Now still in the consideration that, I have just used to make the flashing both the Asus and msi bios with the help of official suggested procedure, and the asus bios is still now the one in my card as I issued the same . Both the asus and msi bios is not going to perform anything even with afterburner voltage control and monitor unlocked and unofficial clocking unlocked.

[Omari]

In the environment of the ATI management , if the VRM is not supposed as the 'software-controllable', it commonly indicates that they are not 'bios-controllable' in both way . Just so you should be aware about this ... don't be entirely surprised if tinkering w/bios is to no available .

By the way , 900c is actually a proper and famous Over-clocking for stock 5850 voltage (1.088V).

[Fitzroy]

That is why even though I have configured the settings in the bios with rbe, the voltages would come back. For example - From 1.25 @ 760/1050 (3d mode for stock 5850 pcs+) to 1.038 (tested by saving the flashed bios with gpu-z).
Thanks guys you helped me and described very well for me, I have decided to stop messing with the bioses and stick with the preconfigured max of 875 for GPU and 1150 for mem (1225 max but its unstable).