GPU Undervolt

I've been trying to find ways to undervolt my GPU for quite some time now. I know there was one post describing how using the Catalyst Control Center's profiles, but that not only had no effect, but it automatically resets itself.

I really want to undervolt to reduced temps and increase battery life. Any help would be greatly appreciated.. if only sending me in the right direction - threads or other websites.

Btw, as can be seen in my signature, I have an MSI GX640 with an ATI Mobility Radeon HD 5850.

Thanks for any help.

 

You will need to extract your vbios with gpuz.
Then use RBE tool to edit the voltage and save your new vbios
Finally you will need a bootable USB stick and atiflash to flash the new vbios.

This could lead to you bricking your machine so if you want to do this I would recommend reading as many guides as possible (a google search will bring up plenty)

 

Have a look
here
or
here

 

I don't know much about 58xx mobile, but I think that the voltages are hard wired. Same as 4850 (mine) and all other previous series, So if there is somebody who knows which resistor to shunt or increase, please
... And by the way, just to mention something when you edit BIOS (related to the last link of tilla) with RBE. If you don't see nothing in the voltage table (down left), thins means that the card is with hard wired voltages (as mentioned earlier). And it doesn't matter what you write for voltage at all. It won't work, though BIOS mod.

 

And why temperatures drops at almost 20°C under fullload (Furmark) at same clockspeed?
It's well explained in the tutorial.

That's right

 

So, @tilla, (By the way do you mean Attila? The great Bulgarian warrior?)
what you mean, there is voltage controller chip in 58xx mobile series? Because the picture you have posted is with empty voltage selector table.

 

Hi Genna,

think so. At 700/1000@1V the temps are higher and voltage lower than 0,95V the card crashed. Dont testet it any longer.

ot:
@tilla is bit of an abbreviation of my daughters name (not tilla) and Attila the Hun.

edit:
But as I wrote, there is maybe an internal wall against too optimistic low voltages. I think at about 0,8 or 0,85V.
You can set 0,7 or some even testet 0,3V (!) for energy saving clocksetting. With no more temperature decrease.
The only tool to show the current voltage I found was GPU Observer Gadget. But this only reads the vBIOS setting.
Please let me know, if you found a other tool to show the voltage of the ATI. Thx