7970 CFX Refusing to overclock

[Bishi]

I have two VTX3D 7970 cards in my machine. They are at the stock clocks 925 / 1375 @ 1174mv.

I have tried to overclock but the highest I could get the core is 1055 before I got errors immediately in OCCT (or the PC just hangs).

Increasing the core voltage doesn't seem to make any difference, in fact if anything it made it worse. I tried the voltage at 1.300 (not intended for 24/7 use, I just wanted to know the limits of my cards) and OCCT crashed even with the cores at 958.

My GPU memory on the other hand seems to work fine, it reaches the max allowed in afterburner (1575) with seemingly no problems.

- Is it harder to overclock these because I am running crossfire?
- Should I have overdrive set to 0% power limit when increasing the voltage manually?
- My 2600k is overclocked to 4.8Ghz (Asrock Extreme7 Gen3) are there any BIOS settings that might be affecting my graphics card OC?


Please advise!

 

[FR@NK]

What are your temps?

Set power to +20

Try first with just a single card.

 

[BarbaricSoul]

first thing I would have done(and I did do this with my crossfire set up) is OC each card by it's self and find out what the cards can do individually. You might have a card that has a problem and that's why you can't get a higher OC.

 

[Bishi]

okay thanks, I'm new to overclocking graphics cards.

Is there a good way to lock the stress testing program to a single card or do i just only run one card with higher clocks and run the stress test full screen so it runs in crossfire (is different frequencies okay for crossfire?)

 

[BarbaricSoul]

okay thanks, I'm new to overclocking graphics cards.

Is there a good way to lock the stress testing program to a single card or do i just only run one card with higher clocks and run the stress test full screen so it runs in crossfire (is different frequencies okay for crossfire?)

Personally, I would do it with just one card in your machine at a time and take notes on what kind of OC each card can do on it's own.

BTW, 1055mhz OC is decent. Just because there are cards that can do alot higher clock, doesn't nessecasily mean both your cards can OC like that.

 

[Crap Daddy]

Would be good to know what PSU do you have. Although the 7970 needs decent amount of power as soon as you overclock the power draw might increase dramatically.

 

[20mmrain]

What are your temps?

Set power to +20

Try first with just a single card.

Both suggestions listed above by both TPU members are a good idea. The one I agree with more is though....is set the AMD Powertune up to 20% and then try the overclocking again.

Another good overclocking tool to try is Trixx..... I found Trixx to be sometimes more stable with overclocking ATI cards then MSI afterburner. Speculated reason: Trixx is made for only ATi video cards MSI afterburner is not. You could also try HIS I-Turbo..... it just came out but it works really really well!

 

[Bishi]

My PSU is a Zalman ZM1000-HP Heatpipe Cooled 1000W Modular PSU

 

[Volkszorn88]

Since you're crossfiring, did you disable ULPS?

 

[Bishi]

I thought I had but i may have missed a few entries (seems there were about 10 in the registry).

Can you please clarify what effect ULPS has on xfire OC?

 

[20mmrain]

http://www.legitreviews.com/article/1488/4/

Read about AMD Powertune

http://forums.guru3d.com/showthread.php?t=334535

Read about Xfire and disabling ULPS and Powertune in MSI afterburner

http://www.guru3d.com/article/radeon-hd-7970-overclock-guide/
http://www.hardocp.com/article/2012/01/09/amd_radeon_hd_7970_overclocking_performance_review/

Read about overclocking the HD 7970

http://www.xcfclan.com/news.php?extend.547.4

Overclocking Guide HD 7000 Series Crossfire

 

[W1zzard]

install sapphire trixx, uncheck the disable ulps option in settings, reboot, enable the disable ulps option in settings, reboot, try oc using trixx

 

[Bishi]

ULPS is definitely disabled now.

I'm monitoring the voltages with GPU-Z and observed the following IDLE desktop and in Heaven benchmark under load
(with unoverclocked GPUs 925/1375, voltage forced constant at 1.174)

GPU 1 IDLE
12V - 12.16V
VDDC - 1.164V
MVDDC - 1.602V
VDDC Current - 18.5A
VDDC Current In - 1.9A

GPU 2 IDLE
12V - 12.09V
VDDC - 1.141V
MVDDC - 1.602V
VDDC Current - 54.8A
VDDC Current In - 6.0A

GPU 1 LOAD
12V - 12.16V
VDDC - 1.129-1.143V
MVDDC - 1.602V
VDDC Current - 30-40A
VDDC Current In - 4-6A

GPU 2 LOAD
12V - 12.06V
VDDC - 1.098-1.131V
MVDDC - 1.602V
VDDC Current - 100-110A
VDDC Current In - 10-12A

Could these disparities in power be the cause of my problems? Is this best fixed by setting the voltage manually for each GPU to accomodate this droop?
I removed my PC CPU overclock while testing.

 

[cadaveca]

If you disabled ULPS, it's likely the second card is running 3D clocks, not low-power 2D clocks, which would explain the higher idle power, but not the load.

Test card #2 on it's own.

 

[Bishi]

If you disabled ULPS, it's likely the second card is running 3D clocks, not low-power 2D clocks, which would explain the higher idle power, but not the load.

Test card #2 on it's own.

im also now using UnofficialOverclockingMode= 2 in afterburner to prevent powerplay and my clocks are forced so they are running at 925/1375@1174 on the desktop.

 

[Bishi]

Thanks for all the advice guys, from testing and overclocking the cards individually I think I have found the issue.. Despite having the same BIOS / card name and everything else... My second card is actually a 1112mv card and not a 1174mv card.

Overclocking the 1174 card (GPU1 lets call it). I found a limit of around 1125 for the core clock), with somewhere between 1.250-1.300V as the required voltage. As this never exceeded 70C under OCCT / Heaven it probably doesn't matter.

Overclocking the second card, it seems very sensitive to voltage. Under increased voltage 1.200V + instant crashes are encountered whenever the core is pushed past stock levels, but despite this it seems to manage 1120 fine on stock voltage (1112mv) and since I probably should have my cards running at the same speeds this is all i can aim for since it is the limit of my first card.

Thats my two cards. 1174 on left, 1112 on right. Both VTX3D 7970's. Obviously similar but with different stock voltages, despite the fact I ordered them from the same place at the same time! (OCUK)

 

[FR@NK]

Can you compare the ASIC quality rating from GPU-Z?

 

[Bishi]

Can you compare the ASIC quality rating from GPU-Z?

This?

 

[FR@NK]

Yep.

Thats why

 

[20mmrain]

My Cards run the exact same way although all I had to do was raise the second card to 1.170 in order to receive the same clocks. See also everyone makes a big thing about a cards ASIC value but I have see cards with an Asic value of 60% and lower do well.... so the ASIC value being low doesn't always mean anything

 

[Bishi]

Yep.

Thats why

Please elaborate

 

[Bishi]

Also possibly a stupid question, but should the cards be running at the exact same core / mem regardless of voltages if they are running in crossfire?

 

[FR@NK]

My Cards run the exact same way although all I had to do was raise the second card to 1.170 in order to receive the same clocks. See also everyone makes a big thing about a cards ASIC value but I have see cards with an Asic value of 60% and lower do well.... so the ASIC value being low doesn't always mean anything

Its why his voltages are different. I wasnt implying that one was better then the other. But I would recommend getting cards that are pretty close if you plan on running crossfire and overclocking.

 

[Bishi]

unfortunately i had no way of knowing, like i say I bought these at the same time.

 

[Bishi]

also strange how the lower rated card had trouble at the higher voltages, but explains the crashes despite its greater OC ability.