Questions Regarding Sapphire 7950 Voltage

Piano Man

Diamond Member
Feb 5, 2000
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So, I'm having a peculiar situation that I'm not sure about. Perhaps it is just my misunderstanding, or it could potentially be a issue.


I just received the SAPPHIRE 100352-2L Radeon HD 7950 http://www.newegg.com/Product/Produc...82E16814202006

I'm using 12.11 Beta and Trixx. OS is Win7 64.

Now, I have made sure that overdrive in CCC is disabled. When I launch GPU-Z 0.6.6 my default VDDC is 0.949V. However, if I move my memory clock just 1 MHz up, that voltage skips up to 1.244V and stays there. I know that in Trixx, VDDC is sometimes hidden and you have to scroll, but I have made sure its set to 950. If I hit reset within Trixx, Voltage comes back down to .949V

Now here is something else. Even at default clocks and voltage, as soon as I go into a game, my voltage goes right back up to 1.244V

Now, I know 1.244V isn't the end of the world, but I don't understand why I can't control it. Does anyone have any advice on this?
 

zaydq

Senior member
Jul 8, 2012
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Thats the turbo boost model you got. I'm unfamiliar with it but i wonder if you flick the bios switch on the card if it goes to a bios that doesnt boost. In order for amd and sapphire to ensure stable boost clocks they pump an obscene 1.25v, which is within tthe safe operating voltage parameters.
 

Piano Man

Diamond Member
Feb 5, 2000
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76
Thats the turbo boost model you got. I'm unfamiliar with it but i wonder if you flick the bios switch on the card if it goes to a bios that doesnt boost. In order for amd and sapphire to ensure stable boost clocks they pump an obscene 1.25v, which is within tthe safe operating voltage parameters.

Thanks for the input. Where is this "switch" you speak of? Is it an old school jumper that is on the physical card? I guess I really never gave the card a once over before installing it.
 

zaydq

Senior member
Jul 8, 2012
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Check around the edges of the card. There will be a tiny black switch with a 1 and 2 marked respectively on the pcb.
 

Piano Man

Diamond Member
Feb 5, 2000
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Found the switch, flicked it over, and the voltage still spikes on me to 1.244V when playing games even though I have Trixxx telling it to stay at .095V

Any other hints?
 

philipma1957

Golden Member
Jan 8, 2012
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Found the switch, flicked it over, and the voltage still spikes on me to 1.244V when playing games even though I have Trixxx telling it to stay at .095V

Any other hints?

try msi afterburner and in the settings set 'force constant voltage'


remove trixx first
 

Piano Man

Diamond Member
Feb 5, 2000
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Philip, that did it! I wonder if I should go back to the default BIOS setting now (flip the switch back). Does anyone know what the difference is? I can't seem to find documentation on it anywhere.
 

zaydq

Senior member
Jul 8, 2012
782
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You can flash a new BIOS on one. The other is a safety in case a mishap occurs.