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6950 -how far is it scaling with the cpu?

VolgoreVolgore Member EpicPosts: 3,872

Hey folks, this one goes out to the geeks out there.

I just upgraded my machine and bought a 6950 and a 2500k. The cpu so far goes easily up to stable 4.8ghz on custom settings, with Vcore offset to -0.100, internal PLL set to 1.7V and LLC set to level2. I havent pushed it any further, although 5ghz ma ybe possible. But so far that already makes some nice overclocking combined with good undervolting,  4.8ghz at steady 1.25Vcore and decent 60° temp at 100% load.

Now, my question ist how far does a single 6950 scale with cpu power anyway? Googling for "6950 cpu  scaling" brings me only crossfire related results and i couldn't yet figure out when the GPU possibly starts to bottleneck. If in case the 6950 gets fully loaded at 3.8ghz already, there would be no need to O'C the cpu any further than that for gaming -unless i was playing a very cpu-heavy game.

Not shure if the above train of thought makes any sense, so i would be glad to get any input from you :)

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Comments

  • ArcheAgeArcheAge Member Posts: 363
    Originally posted by VoIgore

    Hey folks, this one goes out to the geeks out there.
    I just upgraded my machine and bought a 6950 and a 2500k. The cpu so far goes easily up to stable 4.8ghz on custom settings, with Vcore offset to -0.100, internal PLL set to 1.7V and LLC set to level2. I havent pushed it any further, although 5ghz ma ybe possible. But so far that already makes some nice overclocking combined with good undervolting,  4.8ghz at steady 1.25Vcore and decent 60° temp at 100% load.
    Now, my question ist how far does a single 6950 scale with cpu power anyway? Googling for "6950 cpu  scaling" brings me only crossfire related results and i couldn't yet figure out when the GPU possibly starts to bottleneck. If in case the 6950 gets fully loaded at 3.8ghz already, there would be no need to O'C the cpu any further than that for gaming -unless i was playing a very cpu-heavy game.
    Not shure if the above train of thought makes any sense, so i would be glad to get any input from you :)

     

    All your questions wil be answer here plus which 6950 is it?
    overclockers.co.uk go to the forums. Some 6950 overclock to 6970 performace.
  • drazzahdrazzah Member UncommonPosts: 437

    Most games played will utilize your GPU to the fullest before your CPU. So find a super stable overclock (4.7GHz is perfect as long as your cooling is good) and just leave it. Your CPU wont bottleneck you ever. Now, the 6950. I found using MSI Afterburner to be the easiest. You might have to do the config change to unlock the volts. 

    I have a 6950. To be more exact the Sapphire Toxic 2GB one. Stock volts i got to about a stable 945/1425 with the fan. I changed over to a waterblock, pushed the volts to about 1.25 and can easily push it past 1050/1500

     

    ****EDIT****

    Only referenced 6950s will be able to unlock to 6970s. You have to have the dual bios switch on your card and if you just bought your 6950, you most likely dont have a referenced one.

    image

  • czekoskwigelczekoskwigel Member Posts: 458

    Originally posted by drazzah

    Most games played will utilize your GPU to the fullest before your CPU. So find a super stable overclock (4.7GHz is perfect as long as your cooling is good) and just leave it. Your CPU wont bottleneck you ever. Now, the 6950. I found using MSI Afterburner to be the easiest. You might have to do the config change to unlock the volts. 

    I have a 6950. To be more exact the Sapphire Toxic 2GB one. Stock volts i got to about a stable 945/1425 with the fan. I changed over to a waterblock, pushed the volts to about 1.25 and can easily push it past 1050/1500

     

    ****EDIT****

    Only referenced 6950s will be able to unlock to 6970s. You have to have the dual bios switch on your card and if you just bought your 6950, you most likely dont have a referenced one.

    Mine unlocked to the 6970 without any problems.  Even if you can't do it, you can very easily clock it to those speeds without any issues.  You won't get the addtional unlocked shaders, but you can still squeeze a lot of extra power out of it.

  • VolgoreVolgore Member EpicPosts: 3,872

    Thanks so far guys, my 6950 is the Powercolor 6950 2GB 2DH

    http://www.powercolor.com/de/products_features.asp?id=313

    Note that it is not the PCS+ board and the new rev.2 without bios switch, and in case of this particular card it can't be successfully flashed at all. There is a workaround that shortcuts the write protection, but it does not work with every card layout and includes some soldering.

    So i'm going with 900/1250 for the time being, as raising the mem clock didn't provide much performance gain.

     

     

    image
  • RidelynnRidelynn Member EpicPosts: 7,383

    Now this article doesn't exactly address what you are asking, but it comes close. This article looks at triple-GPU setups and how they scale with CPU power. Now, with triple-GPU you would expect some extreme bottlenecking going on, and that's basically what they found, but in the extreme case shown in this article you can draw some inference towards your original question.

    To sum it up, there are some unique situations where the CPU does become the bottleneck, but it's not very common, and mostly only on nVidia cards: the ATI's didn't really scale much at all with CPU.

    http://hardocp.com/article/2011/05/03/nvidia_3way_sli_amd_trifire_redux/6

  • ArcheAgeArcheAge Member Posts: 363

    Originally posted by VoIgore

    Thanks so far guys, my 6950 is the Powercolor 6950 2GB 2DH

    http://www.powercolor.com/de/products_features.asp?id=313

    Note that it is not the PCS+ board and the new rev.2 without bios switch, and in case of this particular card it can't be successfully flashed at all. There is a workaround that shortcuts the write protection, but it does not work with every card layout and includes some soldering.

    So i'm going with 900/1250 for the time being, as raising the mem clock didn't provide much performance gain.

     

     

    Talking about the card,it's not one of the better 6950 to be honest.

     

    Look here.. 

    http://www.overclockers.co.uk/showproduct.php?prodid=GX-128-MS&groupid=701&catid=56&subcat=1752

    http://www.overclockers.co.uk/showproduct.php?prodid=GX-274-SP&groupid=701&catid=56&subcat=1752

     

    These are the 6950s that will give you 6970 performance.

  • drazzahdrazzah Member UncommonPosts: 437

    Yes you can still easily overclock a 6950 to surpass the 6970 and have the clock speeds even be around the 6990 if you have good cooling, but the only thing that wont be there is the unlock shaders.

    image

  • RidelynnRidelynn Member EpicPosts: 7,383


    Originally posted by drazzah
    Yes you can still easily overclock a 6950 to surpass the 6970 and have the clock speeds even be around the 6990 if you have good cooling, but the only thing that wont be there is the unlock shaders.

    Umm, the 6990 stock clock speeds are lower than a 6970, even in it's unlocked mode.

    830 GPU clock (880 in "turbo"), 1250 RAM for the 6990
    versus
    880 GPU clock, 1375 RAM for the 6970

    The 6950 comes in at 800 GPU clock, 1250 RAM, but also has 128 fewer shaders - so it's nearly already clocked at the same speed as a 6990, just need to bump the GPU up 30 Mhz to match clock speeds, and unlock the shaders to match it identically.

    Now what I think you meant to imply is performance. Because the 6990 has dual GPU's, you would have to get a near 100% over clock on the GPU in order to accomplish that (at least for games which support Crossfire), and I don't think that's going to happen. Anything over 900 on the GPU clock is pretty decent for a 6900 series, and 950-960 is about as high as I've seen (and rare at that). Even at 960, your only looking at a 20% over clock.

    I did find one report of a guy with his card at 980 and another at 1020, but they didn't have anything to back that up, so if those are accurate they would be somewhat exceptional outliers - but still a good ways away from the Crossfire performance of a 6990.

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