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Power, Temperature, and Noise: How Loud Can One Card Get?

Last but not least as always is our look at the power consumption, temperatures, and acoustics of the Radeon HD 6990 series. This is an area where AMD has traditionally had an advantage, as their small die strategy leads to less power hungry and cooler products compared to their direct NVIDIA counterparts. Dual-GPU cards like the 6990 tend to increase the benefits of lower power consumption, but heat and noise are always a wildcard.

AMD continues to use a single reference voltage for their cards, so the voltages we see here represent what we’ll see for all reference 6900 series cards. In this case voltage also plays a big part, as PowerTune’s TDP profile is calibrated around a specific voltage.

Radeon HD 6900 Series Voltage
6900 Series Idle 6970 Load 6990 Load
0.9v 1.175v 1.12v

The 6990 idles at the same 0.9v as the rest of the 6900 series. At load under default clocks it runs at 1.12v thanks to AMD’s chip binning, and is a big part of why the card uses as little power as it does for its performance. Overclocked to 880MHz however and we see the core voltage go to 1.175v, the same as the 6970. Power consumption and heat generation will shoot up accordingly, exacerbated by the fact that PowerTune is not in use here.

The 6990’s idle power is consistent with the rest of the 6900 series. At 171W it’s at parity with the 6970CF, while we see the advantage of the 6990’s lower idle TDP versus the 5970 in the form of a 9W advantage over the 5970.

With the 6990, load power under Crysis gives us our first indication that TDP alone can’t be used to predict total power consumption. With a 375W TDP the 6990 should consume less power than 2x200W 6950CF, but in practice the 6950CF setup consumes 21W less. Part of this comes down to the greater CPU load the 6990 can create by allowing for higher framerates, but this doesn’t completely explain the disparity. Compared to the 5970 the 6990 is also much higher than the TDP alone would indicate; the gap of 113W exceeds the 75W TDP difference. Clearly the 6990 truly is a more power hungry card than the 5970.

Meanwhile overclocking does send the power consumption further up, this time to 544W. This is better than the 6970CF at the cost of some performance. Do keep in mind though that at this point we’re dissipating 400W+ off of a single card, which will have repercussions.

Under FurMark PowerTune limits become the defining factor for the 6900 series. Even with PT triggering on all three 6900 cards, the numbers have the 375W 6990 drawing more than the 2x200W 6950CF, this time by 41W, with the 6970CF in turn drawing 51W more. All things considered the 6990’s power consumption is in line with its performance relative to the other 6900 series cards.

As for our 6990OC, overclocked and without PowerTune we see what the 6990 is really capable of in terms of power consumption and heat. 684W is well above the 6970CF (which has PT intact), and is approaching the 570/580 in SLI. We don’t have the ability to measure the power consumption of solely the video card, but based on our data we’re confident the 6990 is pulling at least 500W – and this is one card with one fan dissipating all of that heat. Front and rear case ventilation starts looking really good at this point.

Along with the 6900 series’ improved idle TDP, AMD’s dual-exhaust cooler makes its mark on idle temperatures versus the 5970. At 46C the 6990 is warmer than our average card but not excessively so, and in the meantime it’s 7C cooler than the 5970 which has to contend with GPU2 being cooled with already heated air. A pair of 6900 cards in CF though is still going to beat the dual-exhaust cooler.

When the 5970 came out it was warmer than the 5870CF; the 6990 reverses this trend. At stock clocks the 6990 is a small but measurable 2C cooler than the 6970CF, which as a reminder we run in a “bad” CF configuration by having the cards directly next to each other. There is a noise tradeoff to discuss, but as far as temperatures are concerned these are perfectly reasonable. Even the 6990OC is only 2C warmer.

At stock clocks FurMark does not significantly change the picture. If anything it slightly improves things as PowerTune helps to keep the 6990 in the middle of the pack. Overclock however and the story changes. Without PowerTune to keep power consumption in check that 681W power consumption catches up to us in the form of 94C core temperatures. It’s only a 5C difference, but it’s as hot as we’re willing to let the 6990 get. Further overclocking on our test bed is out of the question.

Finally there’s the matter of noise to contend with. At idle nothing is particularly surprising; the 6990 is an iota louder than the average card, presumably due to the dual-exhaust cooler.

And here’s where it all catches up to us. The Radeon HD 5970 was a loud card, the GTX 580 SLI was even louder, but nothing tops the 6990. The laws of physics are a cruel master, and at some point all the smart engineering in the world won’t completely compensate for the fact that you need a lot of airflow to dissipate 375W of heat. There’s no way around the fact that the 6990 is an extremely loud card; and while games aren’t as bad as FurMark here, it’s still noticeably louder than everything else on a relative basis. Ideally the 6990 requires good airflow and good noise isolation, but the former makes the latter difficult to achieve. Water cooled 6990s will be worth their weight in gold.

Compute Performance Final Thoughts
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  • Figaro56 - Tuesday, March 08, 2011 - link

    Just be prepared to upgrade your GPU every year. If you think they are going to stop leap frogging performance you are not being realistic. Reply
  • san1s - Tuesday, March 08, 2011 - link

    "AMD even went so far as to suggest that reviewers not directly disassemble their 6990"
    The next picture: The card disassembled
    haha
    Reply
  • Ryan Smith - Tuesday, March 08, 2011 - link

    To AMD's credit, they were good sports offered to take any pictures we needed. So all of those disassembled shots came from them. They were really adamant about it being a bad idea to take these things apart if you intended to use them in the future. Reply
  • strikeback03 - Tuesday, March 08, 2011 - link

    I was looking for a comment on whether you did all your testing before disassembling or whether you got some of their super paste to reassemble. Reply
  • 7Enigma - Tuesday, March 08, 2011 - link

    My problem with the shot is the poor application of thermal paste from the picture. In a card of this magnitude having a perfect coating of thermal compound is critical. And knowing marketing if that is the shot they SHOW, how good do you really think the application is on one purchased in retail channels? Reply
  • iwod - Tuesday, March 08, 2011 - link

    I haven't been following CrossFire / SLI or these Single Card Dual GPU closely. ( Which to me are the same as two card anyway )

    Do they still need drivers to have a specific profile of the game to take advantage? I.e an Unknown Game to the Drivers will gain 0 benefits from the 2nd GPU?

    If that is so, then they are not even worth a look.
    Reply
  • Figaro56 - Tuesday, March 08, 2011 - link

    Most of the big games support SLI and CrossfireX today. For example, I play Battlefield BC2 myself and using 2 video cards blows the doors of a single card and is well worth the investment, especially if you have a 2560x1600 resolution monitor like I do. For 2 ATI cards in Crossfire you install a separate crossfire profiles pack in addition to the catalyst drivers. The profiles pack supports all the game crossfire optimization. The AI mode in the catalyst drivers exploits the game profile pack setting for crossfire so you want that enabled.

    A dual GPU HD 6990 is essentially crossfire on a single card, but for some reason it doesn't perform as well as dual single GPU cards in crossfire. Go figure.

    If you play old games that don't support SLI or Crossfire then YES there is 0 gain. If you have not tried any of the new games what are you waiting for? It doesn't suck you know?!
    Reply
  • cactusdog - Tuesday, March 08, 2011 - link

    I agree, unless you have eyefinity and one slot, paying a premium for heat and noise doesnt make sense. For most people with 1 screen a 6970 or 580 is more than enough. Reply
  • Samus - Tuesday, March 08, 2011 - link

    i'd be shocked if they sold even one of these without it being returned at some point. the noise levels are astonishing. at full blast the thing doesn't even meet federal vehicle emissions noise regulations without being classified as a motorcycle! Reply
  • MadAd - Tuesday, March 08, 2011 - link

    8%? where do we buy tubes of this phase change material? do they sell it like arctic silver? Reply

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