Overclocking VisionTek 6970 - Your experiences?

[full_out]

I am playing with the clock settings on my VisionTek 6970. I'm just wondering what other experiences people have with these cards. What were you able to max them out at? What temps where you getting?

Right now under load at stock settings I am getting around 80C. Seems high to me, because my fully overclocked Sapphire 5850s crossfired were maxing out at about 75C. But from what I have read, 6970s should be able to get up to 100C or more.

Any input would be nice, I'm just trying to get a feel on my newly acquired card

 

[larkspur]

Read about powertune: http://www.tomshardware.com/reviews/radeon-hd-6970-radeon-hd-6950-cayman,2818-5.html

Use a good overclocking utility like msi afterburner.

I have a non-reference Asus directcu 6970. I had to use Asus GPU tweak since afterburner didn't support voltage tweaks on my particular card. I noticed that by bumping the voltage to 1.2v I could get 980mhz on the core. Unfortunately I had to manually set the fan way too loud for my tastes @60% to keep temps under 90 at that voltage. I didn't go any further because I prefer my computer to not sound like a vacuum cleaner.

I benched using Furmark (be careful with Furmark, it really does make your GPU hot) and 3dMark11. And games of course. Remember that you can often get through benches just fine and end up with crashes when actually playing in games, so testing your overclock can be a bit time consuming.

I settled on 950mhz at default voltage which peaks at 81c in my hot, wood-stove heated basement with fan on auto that doesn't exceed 45%.

With regards to memory overclocking. From what I've heard the error correction is very robust on vram and you might find what appears to be a 'stable' vram overclock but benchmark performance is actually lower. My memory didn't clock past 1400mhz without decreased performance. So basically bump it up and watch your benchmarks.

With regards to heat - I don't like my 6970 running at higher than 85c. I know that they can run up to 100c before 'shutting themselves down' but I believe that temps above 85c are considered above normal operating range and will have a particularly negative effect on the longevity of the chip. While testing temp using Furmark, I kept a close eye on the bench and shut it off if the temps got above 90c since that is my own somewhat conservative cut-off.

 

[full_out]

Sweet thanks for the info. I will try Furmark. I was using Kombuster last night and my temps didn't get even close to what they did when I tried BF3 after. It's weird, I find my 5850s overclocked so much better. I figured the 6970 would overclock much better, but it seems the other way around at this point. Oh well. I'll keep plugging away.

 

[larkspur]

Sweet thanks for the info. I will try Furmark. I was using Kombuster last night and my temps didn't get even close to what they did when I tried BF3 after. It's weird, I find my 5850s overclocked so much better. I figured the 6970 would overclock much better, but it seems the other way around at this point. Oh well. I'll keep plugging away.

Usually the high-end chips aren't as good overclockers as the mid-range. This is because they already push the thermal limits of their design. AMD powertune makes this even worse because they are already squeezing a pseudo "overclock" out of their cards by using powertune to allow them to clock them higher at stock than they otherwise could.

You'll find that the FPS increase is pretty minimal when overclocking the 6970. It'll vary game to game but won't be much. It's still fun though! You can also mess around with undervolting the card to decrease the temps.

 

[full_out]

Well that makes sense. Thanks for the info

 

[full_out]

Well I played with my fan profile in Afterburner and was able to get my temps down to 71C under full load without being to horrendously loud. I will be pushing my clocks a little higher tonight (hopefully the GF won't get to pissed lol). I'll report back later.

 

[full_out]

Pushed my card to 910/1400 then get to lazy to go further. Thanks for the advise though!

 

[full_out]

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