How to Overclock Voltage on Sapphire 6950 2Gb Dirt3 edition

[akamikeym]

This is my first go at doing any GPU overclocking and it's been a bit rough so having now managed to figure out how to at least change the settings I need with my card I would post it in case anyone else is in the same boat.

My card the Sapphire 6950 2Gb Dirt3 edition seems to be rather difficult to modify the Voltage on along with the clock speeds without glitching. ALL programs other than AMD's own Graphics Overdrive in CCC caused graphical glitching whenever setting clock speeds (even when setting them to the stock settings!). That includes Sapphire's own Sapphire Trixx (4.1.0 and 4.3.0).

Thanks to this board I found a thread on unlocking the caps set by CCC and using MSI Afterburner the official way. This allowed me to overclock using MSI Afterburner without glitching as well, but unfortunately still not set the Voltage. MSI afterburner even with cfg tweeks would not allow me to set the Voltage.

Eventually I found another thread showing a method of modifying the Voltage by manually editing the CCC profile. I thought I would post the steps here.

1. Completely close CCC. I achieved this by killing CCC.exe with Task Manager and making sure it didn't respawn.
2. Use Explorer to go to "%AppData%\..\Local\ATI\ACE" (for my system this is "C:\Users\myusername\AppData\Local\ATI\ACE").
3. Edit "Profiles.xml" with a text editor.
4. Find a section that looks like this:
   

   <Feature name="CoreVoltageTarget_0">
       <Property name="Want_0" value="900" />
       <Property name="Want_1" value="1020" />
       <Property name="Want_2" value="1100" />
   </Feature>

   where the "_0" at the end of "CoreVoltageTarget" can be the name of your card. I found I had 2 of these sections in my Profiles.xml file and I wasn't sure which one set my card so i modified them both.
5. Change the value of property "Want_2" to the voltage you require so 1.180V would be:
   

       <Property name="Want_2" value="1180" />

   the "Want_2" appears to be the high performance setting for in games or benchmarking (can't be more certain than that I'm afraid).
6. Start up CCC again. (edit) Possibly requires restart instead of this step - to be confirmed.
7. Apply Overclocking settings in Graphics Overdrive and apply.
8. Check your Voltage settings while benchmarking for example using MSI Kombustor. It should now be set to your new value.

Phew! That should be it.

 

[akamikeym]

Nope, doesn't unlock voltages for me. I have to admit that I hadn't thought of this, I had switched back to using the basic BIOS setting some time ago to see if some trouble I was having was its fault. However testing the BIOS with the unlocked shaders on my card now still doesn't give me Voltage control. I hadn't really thought of the BIOS route is there any way to unlock Voltage control in Afterburner by modifying my BIOS, say with RBE?

 

[akamikeym]

Also I raised the question of why Sapphire Trixx has disabled Voltage control in 4.3.0 with Sapphire who said this:

Dear Sir
Sapphire follow AMD rule, so we change to power limit on new version. You can rollback to previous version. Sorry about that.
Regards

(edit) I wouldn't mind them switching it for Power Limit if it behaved sensibly and managed voltage control for you, instead it leaves it stuck on 1.10V no matter what setting you use. Looking at my BIOS volt settings that's actually lower than the boot Powerplay state.

 

[akamikeym]

Hi Davedree,

Yes I'm an idiot, you're right. I can't believe I didn't move the scroll bar in Sapphire Trixx down. For some reason I thought it was just an issue with their big graphics not fitting into the container they'd given it.

I've not been able to find a copy of Afterburner 2.1.0 to try it out but 2.2.5 and 2.2.5 betta both refuse to allow Volting on my card (I've not idea why since Sapphire Trixx at least allows some). My method seems to work as long as I restrict myself to using CCC and don't use AB which sets the profile Voltage back down to 1.10V.

I wouldn't have minded getting a Voltage set in my BIOS as I use Linux as well and it would be nice for the Overclock to hold for both, as I do for my CPU but it seems to refuse to work. My card's BIOS and RBE doesn't allow me access to GPU Registers so I can't set the Voltage in there. I've tried setting it by hand in the Voltage section of Clock Info 03 which appears to correspond to my high performance profile, but it has a weird default of "---" and just bombs out when booting windows (after the windows logo animation). For some weird reason Linux will boot fine with that BIOS but who knows what it's doing.