OC: Power, Temperature, & Noise

Our final task is our look at the 7970GE’s overclocking capabilities. As the 7970GE is based on the existing 7970 we aren’t expecting any significant changes, however it’s reasonable to expect that general manufacturing process improvements over the last 6 months will have pushed yields and tolerances a little higher, giving us just a bit more headroom.

At the same time the presence of the boost clock and its associated voltage is going to change overclocking as well. The higher voltage should lend itself to higher overclocks, meanwhile validating overclocks is also going to be a bit harder as now we need to make sure neither the overclocked base clock/voltage combination or the overclocked boost clock/voltage combination is unstable, similar to the extra effort needed to overclock the GTX 680 series.

Radeon HD 7970 Series Overclocking
  Ref 7970GE Ref 7970 XFX 7970 BEDD
Shipping Core Clock 1000MHz 925MHz 1000MHz
Shipping Max Boost Clock 1050MHz N/A N/A
Shipping Memory Clock 6GHz 5.5GHz 5.7GHz
Shipping Max Voltage 1.218v 1.175v 1.175v
       
Overclock Core Clock 1150MHz 1100MHz 1125MHz
Overclock Max Boost Clock 1200MHz N/A N/A
Overclock Memory Clock 6.4GHz 6.3GHz 6.3GHz
Overclock Max Boost Voltage 1.218v 1.175v 1.175v

After going through the full validation process we were able to hit an overclock of +150MHz, which pushed our base clock from 1000MHz to 1150MHz, and our boost clock from 1050MHz to 1200MHz. Depending on how you want to count this overclock amidst the presence of the boost clock this is either 25MHz better than our best 7970 card, or 75MHz better. In either case our 7970GE definitely overclocks better than our earlier 7970 cards but not significantly so, which is in-line with our expectations.

As with any overclocking effort based on a single sample our overclocking results are not going to be representative of what every card can do, but they are reasonable. With AMD now binning chips for the 7970GE we’d expect to see some stratification among the 7970 family such that high overclocking chips that would previously show up in 7970 cards will now show up in 7970GE cards instead. For penny-pinching overclockers this is not good news, but for more hardcore overclockers this is nothing new as AMD’s partners have been doing something similar with their factory overclocked cards for some time now.

Meanwhile our memory overclock isn’t significantly different from what we could pull off with the reference 7970. The limitation is the memory bus or Tahiti’s memory controller, neither of which has changed. After around 6.4GHz errors start catching up and performance gains become performance losses.

Moving on to our performance charts, we’re going to once again start with power, temperature, and noise, before moving on to gaming performance. We’ll be testing our 7970 cards with the PowerTune limit set to +20% in order to avoid any real possibility of being performance limited by PowerTune.

With the 7970GE’s already high load power, overclocking and raising the PowerTune limits isn’t doing it any favors when it comes to overclocking. On the contrary to being a free overclock power consumption now exceeds even the GTX 690 in all situations and power consumption is almost certainly in excess of 300W at the card level. As we’ll see in our gaming performance section we’re definitely getting more performance out of the 7970GE, but we’re paying for it with power.

With a rise in power consumption comes a rise in temperatures to a varying degree. At 83C under Metro the 7970GE has gotten warmer, but not significantly so. The same cannot be said for OCCT. At 89C we’re approaching the reasonable limits for this card and cooler.

The 7970GE was already loud at stock and overclocking it doesn’t help. Under Metro noise is now at 63.8dBA, and under OCCT it’s tied with the 6990 for noise at 66dBA. Even if you’re forgiving of noise, this is reaching the point where it’s going to be difficult to ignore. Serious 7970GE overclockers will want to seek other cards and/or aftermarket coolers.

Power, Temperature, & Noise OC: Gaming Performance
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  • AnnihilatorX - Friday, June 22, 2012 - link

    "All the same AMD has also boosted their memory clocks from 5.5GHz to 6GHz, which will give the card 9% more memory bandwidth with it needs it."
    =>
    "when it needs it"
    Reply
  • raghu78 - Friday, June 22, 2012 - link

    Ryan
    As you mentioned Dirt Showdown will take the place of Dirt 3 in your test suite I would like to make a suggestion that a few more games be changed. Max Payne 3 and Alan Wake are good changes. Maybe Crysis Warhead could be replaced by Alan Wake and Portal 2 by Max Payne 3. Another very demanding game which could find a place is Witcher 2 Enhanced edition. Focusing on games released in the last 12 months in your test suite helps prospective buyers / gamers decide based on performance on recent titles which they will most probably be playing.
    Reply
  • HighTech4US - Friday, June 22, 2012 - link

    You are showing the OCed version of the 7970e in comparison to the stock GTX680.

    For fairness the stock GTX680 should be Overclocked also.
    Reply
  • kyuu - Friday, June 22, 2012 - link

    There's nothing fair or unfair about overclocking. Why do people bring this up every time there's one of these articles... Reply
  • CeriseCogburn - Saturday, June 23, 2012 - link

    Good to hear it this time, as all the prior moaning has been amd fans wailing that the 680 core is already overclocked out of the box !
    L M H O

    I just want to see the 470, 480, 570, and 580 at the equivalent radeon clocks for those series, and see amd get SPANKED even more in those series.... to be fair, of course....

    Yes, thanks so much for saying "you guys always say it" - no - it's not "you guys" - it's the amd fan boys !

    This time they didn't moan and complain about fairness, because amd got beat anyway, and they wouldn't if it won, which it did not, I must point out, feeling the overwhelming need to state, again, and again.

    This sums it up well: AMD loses, as usual

    Reply
  • seapeople - Friday, June 22, 2012 - link

    They're also comparing the OCed version of the 7970e to the stock 7970e. That seems unfair to me. To be fair, you should only compare the OCed 7970e to itself, the OCed 7970e. Reply
  • Arbie - Friday, June 22, 2012 - link


    It's probably too late now, but there were at least three more places where you could have used "performance crown" in the opening paragraphs.
    Reply
  • CeriseCogburn - Saturday, June 23, 2012 - link

    Amd LIED, with their false advertising about this card - their hot loud slow housefire...

    Amd is an evil corporate monster who lies to the little children they sell their products to (and to soccer Mommies who actually pay the card price to keep the lies going - granted they pay less than Abu Dhabi oil sheiks)
    Reply
  • Wreckage - Friday, June 22, 2012 - link

    Another successful paperlaunch

    I'm not sure why they could not wait until they had actual product available.
    Reply
  • behrouz - Friday, June 22, 2012 - link

    AMD Radeon HD 7970 GHz Edition = $499
    AMD Radeon HD 7970 = $549 ? or $449 ?
    Reply

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