Sapphire 7970 MASSIVE vdroop under load

[STaRGaZeR]

Hi there! First post on TPU!

I recently bought a Sapphire 7970 NON OC version with the blue PCB, one of those close-to-but-not-like reference models. The exact model number is 11197-11-40G. Everything is nice and all, but there's this little problem that is killing my OC. The card has massive amounts of vdroop on the core under load, checked with a multimeter. For example:

VID ------- vcore idle ---- vcore load ---- multimeter idle ---- multimeter load ---- vdroop

1.300V ----- 1.299V ------ 1.175V --------- 1.298V ------------ 1.163V --------- 0.136V

With a lower VID, say 1.200V, vdroop is lower but still around the ~0.1V mark. As you can imagine this is bad for OC and for the card itself.

Any suggestions or mods that don't require any soldering? I can take photos of the PCB if needed.

Thanks!!

 

[Aquinus]

I'm not sure if there is much you can do in general. Usually its the VRMs the introduce vdroop to protect hardware (since voltage changes can overshoot then equalize out every time it changes voltage due to how VRMs work,). I don't think there are any homebrew mods you can do to eliminate this short of replacing the card or increasing the voltage more which might not be a good idea depending on how stressed the VRMs already are.

It could be temperature related but I doubt it. Just for shits and grins, what do your temperatures look like under load?

 

[STaRGaZeR]

About 40ºC under max load (WC'ed). I measured it before with the stock cooler, temps were a lot higher but vdroop was more or less the same.

 

[Frogger]

these card are infamous for their droop. Hardmod is the only way your going to adjust it but it's really not worth it for the effort needed for the mod & your card is non-reference so you might not find 1 for your card. Your card is WC'ed so you could adjust the v's with a modded Trixx [4.40b] so its not as bad

 

[STaRGaZeR]

You mean it's a problem common to all 7970 or just Sapphire? I've found some reports of droop on 7970s, Sapphire and Asus, neither as big as mine though.

Do you guys think 1.35V is going to be too much for light gaming? When idle I'm using 0.9V and it's all good, under heavy load the droop is going to be around 1.20V, but under light load the volts are going to be close to 1.35V, which is quite high IMO.

 

[the54thvoid]

My Powercolor HD7970 (water cooled version) had a maximum Voltage of 1.3v in Afterburner. That got me to 1300MHz core. It was a stock pcb. Isn't 1.35v a tad high for a non custom vrm?

 

[STaRGaZeR]

You're right, it seems 1.3V is the max for me too. Damnit, that leaves a maximum voltage under load of 1.16V

 

[cadaveca]

You're right, it seems 1.3V is the max for me too. Damnit, that leaves a maximum voltage under load of 1.16V

Yeah, and that's perfectly normal, unfortunately. Droop on 79-series cards relates directly to the amount of power the GPU consumes. Some cards will droop less, for sure, but large droop is the name of the game with 7970. My Matrix card goes from 1.256 down to 1.16V-1.14V, roughly the same as yours. My card offers the ability to adjust loadline via software, however.

 

[samsal]

I also have this card
check this
http://www.techpowerup.com/forums/showthread.php?p=2887636
I OC it with MSI AB from 925/1375-1025v in MSI AB
to 1100/1500-1150v
and it is working just fine
and, yes there is vdroop

also you could try force constant volt from MSI AB

and it is good to share your OC setting

 

[STaRGaZeR]

Yeah, and that's perfectly normal, unfortunately. Droop on 79-series cards relates directly to the amount of power the GPU consumes. Some cards will droop less, for sure, but large droop is the name of the game with 7970. My Matrix card goes from 1.256 down to 1.16V-1.14V, roughly the same as yours. My card offers the ability to adjust loadline via software, however.

Bummer, it really kills a lot of OC potential. What do you mean adjust via software? Using some Asus program? What clocks are you able to get with that voltage? Are those voltages loadline adjusted or not?

I also have this card
check this
http://www.techpowerup.com/forums/showthread.php?p=2887636
I OC it with MSI AB from 925/1375-1025v in MSI AB
to 1100/1500-1150v
and it is working just fine
and, yes there is vdroop

also you could try force constant volt from MSI AB

and it is good to share your OC setting

I already use AB, that's how I set fixed voltages for 2D and 3D. I need 1.20V (around 1.10V real) for 1125Mhz on the core, I have to test more. With 1.30V (1.16V real) 1200Mhz is a bit unstable.

BTW, do you have the original 2 BIOS? I flashed mine without making a backup first

 

[cadaveca]

Bummer, it really kills a lot of OC potential. What do you mean adjust via software? Using some Asus program? What clocks are you able to get with that voltage? Are those voltages loadline adjusted or not?

ASUS software, yes. Reference cards with ASUS ROG VTweak(R4E, R5E) boards can get software control with mods, too.

Droop does affect clocks in some instances. But not really at the high-end, that I have found. What AMD offers seems fine to me, ensures that GPUs remain relatively safe under increased voltage.


For my card, adjusting voltages means little, but I can clock my Matrix to 1200 MHz on stock 7970 voltage(1.17V) anyway.

Loadline can be adjusted via the ASUS software with this Matrix card only. I also ahd DirectCUII 7970, it did not offer that.

 

[samsal]

yes, I still have the original bios on one side

 

[STaRGaZeR]

ASUS software, yes. Reference cards with ASUS ROG VTweak(R4E, R5E) boards can get software control with mods, too.

Droop does affect clocks in some instances. But not really at the high-end, that I have found. What AMD offers seems fine to me, ensures that GPUs remain relatively safe under increased voltage.


For my card, adjusting voltages means little, but I can clock my Matrix to 1200 MHz on stock 7970 voltage(1.17V) anyway.

Loadline can be adjusted via the ASUS software with this Matrix card only. I also ahd DirectCUII 7970, it did not offer that.

Nice, thanks for the info. I'm fine with vdroop as long as it's not that large. While it does protect the card under increased voltage at high loads, if the load is low the voltage doesn't droop, and when you're running close to 1.3V now that's dangerous.

yes, I still have the original bios on one side

Can you share it, please?

 

[samsal]

I am not sure if it is the right way to do it
but you can try and tell the result
http://www.sendspace.com/file/gfi89v
I am new in this thing

 

[STaRGaZeR]

I am not sure if it is the right way to do it
but you can try and tell the result
http://www.sendspace.com/file/gfi89v
I am new in this thing

Thanks mate, I'll flash it when I get home. Will tell you the result.

 

[STaRGaZeR]

I am not sure if it is the right way to do it
but you can try and tell the result
http://www.sendspace.com/file/gfi89v
I am new in this thing

Tried it, it's the same as the one here: http://www.techpowerup.com/vgabios/131192/Sapphire.HD7970.3072.120926_1.html

Works more or less like the others I've flashed, thanks . Do you know what are the clocks of the original second BIOS?

 

[erocker]

I've tried every bios that will work with my card. None of them fixes the vdroop.

This is what I get:

 

[samsal]

Tried it, it's the same as the one here: http://www.techpowerup.com/vgabios/131192/Sapphire.HD7970.3072.120926_1.html

Works more or less like the others I've flashed, thanks . Do you know what are the clocks of the original second BIOS?

I think it was 925/1375 on both side