Help needed with overclocking unlocked XFX 6950

A

amd7674

[H]ard|Gawd
Joined
Jan 1, 2007
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I’m new ATI user and I’ve always used Afterburner to set voltages/clock/fan profile and OCCT for stability tests on my previous nvidia cards.

At the moment I’m using the latest Afterburner 2.1 Final with modified config file to:
UnofficialOverclockingEULA set to: I confirm that I am aware of unofficial overclocking limitations and fully understand that MSI will not provide me any support on it
UnofficialOverclockingMode set to 1 to keep PowerPlay active (may not work on old ASICs)
I did replace TIM with MX-4, but I found XFX already did good job with my card and I’ve only gained 1C-3C at best. Last night I did play a little bit with overclocking my card. I used OCCT (35 minutes run, native rez, full screen with error checking). The best stable clock on stock voltage I got was 860/1300… However with limited time I had I couldn’t get anywhere with 1.15V tiny bump in Afterburner (2.1 Final)… On the first attempt 900/1300 with Powerplay set at +0% and 1.15V, after few minutes, OCCT exited to the desktop with almost black screen with only few icons displayed… So with alt+tab+del I was able to restart the system. It looks like not enough voltage or wattage (I did try increasing PP to +20% without luck). Afterburner runs automatically on the system start.

Also like mentioned by others any voltage changed in Afterburner 2.1 Final is not reflected in GPU-Z or any other software and still shows 1.1V. However some say that it doesn’t matter, because the voltage is still changed. Now if I go to CCC I cannot uncheck overdrive in CCC, and GPU clock slider disappeared??? Also now I cannot disable overdrive option in CCC, every time I uncheck the box and hit apply the box gets re-checked again. I wonder if that has something to do with memory overclocked in Afterbuner to 1300 from default 1250. Perhaps my overclocking attempts broke CCC’s config files or worst its registry settings… ???

So, should increase voltage to more 1.175V in afterburner? Use something else to increase voltage? Use something else than OCCT for stability
test? Increase fan speed?

With 860/1300 and custom fan profile I’m getting 83C with fan at 42% after 35 minutes of OCCT, which is great because this means 5-20C less while playing games. Overall I’m very happy with the card, I’m just wondering if I can push GPU a little bit more.

TIA ;)
 
I see the sliders disappear in CCC as well. I just assumed that Afterburner "took control" over them so as not to allow conflicting settings. I'm pretty sure the sliders will reappear if Afterbuner is not running but I am not at home so I can't check that. Do you have Afterburner set to startup automatically?

As for voltage, yes bump it up to at least 1.175V. I tried voltages up to 1.2V without issue but found 1.18V was the sweet spot for my card. I think others have even gone up to 1.3V to get the core up to 1000 but
I did not want to push the stock cooler that hard.
 
Thanks HoucusPocus :p

Yes Afterburner starts automatically. Weird though the mem slider is still shown... I'm glad this seems to be "normal" behaviour...

How do you test your GPU's stability? I'm wondering if using OCCT is the way to go... it is heavy on wattage, and it requires using power tune to be set to +20%. I believe furmark is a little lighter on wattage, perhaps I should use it instead of OCCT. How deos your fan profile look like? What is the max temp you are getting at load?

Thanks.. ;)
 
I've used Kombuster and/or Furmark as a quick gauge of stability. If Furmark would run for 5+ minutes I would bump up the clock speed and try again. At 950 core, my card would lock up even with 1.2V so I stopped at 940. At 940, I ran a longer session of Furmark making sure temps leveled out and I've also been playing Crysis, BC2 and Monday Night Combat. I have OCCT installed and plan on running that at some point as well. I may also try Folding for a day or two on it, I've done that in the past.

Personally, I think it's very difficult to "prove" stability of a GPU OC using just 2 or 3 programs. I try to test with a variety of apps until I am reasonably comfortable that the OC is stable. Even then I don't think I've proven stability. Then I go and play my games with the expectation that one day I may hit an error :)

My approach on temps was to keep all 3 temps reported by GPU-Z under 90 C when running Furmark. I ramped my fan profile accordingly. I'll have to look at it again, but I think I keep the fan speed below 50% until temps cross the 80 C mark.
 
Thanks for sharing your info... Are you using CCC's PowerTune at all from deafault +0%?

EDIT:
Should I have CCC running in the background along with AB?... or should I adjust all necessary settings and prevent it from starting with windows?
 
Last edited:
I have CCC running in the background and PowerTune at +20% so that it would not be a limiting factor. I may try some testing later on to see if I can leave PowerTune at 0. It would be nice to be able to leave PowerTune at 0 given I have had it reset to 0 a few times on me, probably after a crash or lockup.
 
[H]ocusPocus;1037005888 said:
I have CCC running in the background and PowerTune at +20% so that it would not be a limiting factor. I may try some testing later on to see if I can leave PowerTune at 0. It would be nice to be able to leave PowerTune at 0 given I have had it reset to 0 a few times on me, probably after a crash or lockup.
Click to expand...

thanks, please try OCCT with PT set to +0% when you get a chance ;)
 
I checked my fan profile. Right now I have it ramping linearly from 25% at 30C to 50% at 70C. It continues up to 58% at 80C, 70% at 85C and 100% at 94C. I game with headphones on so fan noise is not a big issue for me.

I'll try OCCT as soon as I can.
 
I did some quick testing...

OCCT needs +15% PowerTune setting else I see core speed clock throttling. I ran it for 10 minutes, no errors, max temp 70C (very cool room though).

Furmark needs +20% PowerTune setting else I see throttling. Max temp was the same.
 
Thanks so much for the data... I'll have now something to chew on ;)

How can you tell GPU is throttling? GPU speed and usage in AB? I wish OCCT would display 6950 when running test...

Wow 70C in OCCT with your settings... not bad at all... I can see your fan profile is much more aggressive than my. Perhaps I should adjust my...

BTW.. do you have GPU/mem slider in your CCC settings?
 
So I thought I had a stable 900/1325 @ 1.175V with CCC’s PT set to +0%, and just before I went to bed I’ve tried Unigine Heaven 2.1 (DX9 x2AA 1680x1050, high settings, full screen) and it did freeze right in the middle. Right after I’ve got display driver stopped working and was successfully restored…blah..blah… Next I tried to up voltage to 1.800V, however Heaven 2.1 would still freeze. I’ll run tests again with the latest Heaven 2.5 release. Also I’ll try my previous 860/1300 @ 1.1V settings which I never tried with Heaven benchmark. If that fails I’ll go back to stock 800/1250. As a last resort I’ll re-flush card back with my original BIOS (unlocked). Also I’ll try HocusPocus's more aggressive fan profile…

It is quiet possible I have a weak GPU or unlocked shaders are causing instability issues… hmmm
 
By throttling, I mean I can see the core speed being raised and lowered dynamically. And yes, I use Afterburner to see this.

At 900 core and 1.175V it is highly likely you are getting throttling and maybe that is causing the freezing? You should try adjusting PT up as your card is probably now consuming more power than a stock 6970.
 
HocusPocus thanks for all your help.... ;)

It was late last night, so I might revisit my testing again....

From now on I'll use +20% PT and yours more agressive fan profile. Also instead of going for a "home run" I will start with 880/1250 (GPU/mem) at 1.175V and I will go from there.... (sometimes o/c ddr5 can be a problem)

I have a decent PSU, which should not have any issues handling higher wattage... i just hope video card can handle increased voltage and +20% PT...
 
You'll need a bit more voltage if you want to hit higher frequencies. I need at least 1.2v for anything over 900 and it safely hits 920 max at that voltage. I'm not sure if it's entirely stable at that voltage and core speed but I haven't had any of my games or display driver crash at this setting.
 
rUmX said:
You'll need a bit more voltage if you want to hit higher frequencies. I need at least 1.2v for anything over 900 and it safely hits 920 max at that voltage. I'm not sure if it's entirely stable at that voltage and core speed but I haven't had any of my games or display driver crash at this setting.
Click to expand...

Thanks... What setting are you using for power control? +20%?
 
Yup, I have mine set at +20%. I don't see a reason why we shouldn't. Throttling is not cool.
 
Thanks everyone for your help. ;) I played a little again last night with o/c and I thought I had 900mhz GPU stable (30 minutes in Furrmark), however it it froze my Mafia 2 game after an hour of gaming… It is possible my fan profile is not aggressive enough, where I’m not willing to go over 45% fan speed. If I ever upgrade HSF with Shaman or something I might revisit this again. Currently I have a stable 850/1300 @ 1.1V with power control set to +0%. I use afterburner to monitor games and if I find any of my games throttling GPU, I’ll increase PC to 10-20% range. With my current setup I don’t think it is worth to spend time/effort to go to 900Mhz range, to gain hmmm…. 5% boost... I don’t think it will make much difference in games like Crysis or Metro 2033.

Overall I’m very happy from my purchase and I would buy it again. :D
 
I didn't thoroughly read the whole thread, but are you re-applying your PowerTune settings every single time you change your clocks? It's necessary. As far as the fan goes, adjust it to maintain stability; the chip will be more sensitive the higher the clocks you go.
 
Mr. K6 said:
I didn't thoroughly read the whole thread, but are you re-applying your PowerTune settings every single time you change your clocks? It's necessary. As far as the fan goes, adjust it to maintain stability; the chip will be more sensitive the higher the clocks you go.
Click to expand...

No I haven't. hmm.. However sometimes I did notice PT settings defaulting to +0% for power control. I was under impression that failing driver due to overclock would do that. So everytime I change clocks in AB I should check/adjust PC in PT?

Wow, Is your GPU under water? wow very nice clock 1Ghz+ ;)
 
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