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Power, Temperature, & Noise

Last but not least as always is our look at the power consumption, temperatures, and acoustics of the Radeon HD 6790. Our power usage data should closely mirror any other 6790, but given the unique design of our card versus what AMD’s partners are going with, we can’t fully account for all the different designs.

On that note, at this point we do not know what the 6790’s default voltage is. None of our usual low-level tools recognize the 6790; it’s possible that AMD is using different controllers than on the 6800 series, or perhaps it’s related to drivers. In any case we believe it’s close to the 6870’s voltage of 1.17v, but we can’t measure it at this time.

Idle power consumption rarely changes among the different tiers of a GPU, so the fact that the 6790 pulls almost as much power at idle as the 6800 series should not come as a surprise. It does end up being worse than the GTX 550 Ti, but almost exactly alike the GTX 460.

Given AMD’s TDP numbers, we were expecting our power results to closely shadow our 6870 results. Instead we had a pleasant surprise: power consumption under Crysis is higher than the 6850, but not significantly so. In fact it’s still below the GTX 550 Ti even though it significantly outperforms said video card on this game, and even compared to the 5770 it’s not significantly worse for the 6790’s performance advantage. Not that it’s great to be consuming more power than a 6850 for less performance, but it could very well have been worse.

The situation under Furmark is even better surprisingly enough. The 6790 consumes less power than the 6850 here – not a ton less, but less. Perhaps more surprising is that compared to the 5770 it’s only consuming 3W more; this Barts chip may have a lot of functional units disabled, but that’s still quite remarkable, and is all the more proof of the optimizations AMD made for Barts compared to Cypress. This also makes it look exceptionally good versus the GTX 550 Ti and GTX 460 768MB, as it’s consuming 40-45W less.

With idle power consumption being identical to the 6800 series and using the same cooler, the idle temperature is similarly close.

Given the power numbers we saw earlier, the 6870’s cooler ends up being overkill for the 6790. As a result Crysis temperatures are quite low, although the fully exhausting cooler can’t keep up with the open cooler of the GTX 460. Then again our 5770 is an open cooler, and it’s still much warmer. Keep in mind that this is going to highly vary with the design of the cooler the partner uses though.

Temperatures under Furmark closely trend Crysis. An open cooler might be able to get the 6790 down to the low 70s.

Idle noise is identical to the 6800 series, as we’d expect.

Load noise is where the wheels begin to fall off on our 6790 sample. The card does so well with regards to power consumption and temperature, but noise is just as bad as the 6870. This undoubtedly is due to how AMD tweaked the 6790 engineering sample – which is to say it likely hasn’t been optimized much if at all since it won’t go into production. Given the power data we’ve seen the 6790 doesn’t need to be much louder than a 6850, so hopefully partner cards will reflect this. If not, the worst case scenario may very well be having all the noise of a 6870 and not nearly the performance.

Compute & Tessellation Final Thoughts
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  • Ryan Smith - Tuesday, April 05, 2011 - link

    As a matter of editorial policy I don't like to base my conclusions around future card availability; the only thing for sure about the future is that it's not what I expect it to be.

    "Discontinued" cards are normally available for quite a long time after they're launched, and for the time being the GTX 460 768MB is readily available online and at retail for very good prices.
    Reply
  • silverblue - Tuesday, April 05, 2011 - link

    You only have to think of other "discontinued" products to remember how popular they were for a good time after they were no longer produced - the Radeon HD 4850, NVIDIA GeForce GTX 250 and the AMD Phenom II X3 720 BE spring to mind. Reply
  • jabber - Tuesday, April 05, 2011 - link

    ...simply install another 5770.

    Well its what I did.

    Wonder how the 5770 stacks up to the 6790 with 900/5000+ OC.
    Reply
  • marc1000 - Tuesday, April 05, 2011 - link

    I would love to see some RECENT tests with the 5770 CF... all reviews available are from the time of launch, comparing it with the 5870 only and in old games.

    it would be nice to have a recent comparison of CF/SLI from previously mainstream cards (5770/460)

    :-(
    Reply
  • fingerbob69 - Tuesday, April 05, 2011 - link

    ...this card plays most games with all the effects on full. I want to change it but can't see the point.

    I think the HD7xxx are gonna be game changers though with the bump in performance quite huge compared to HD4xxx and HD5xxx levels.

    As to wether any games are about to test the "*nm cards is another question.
    Reply
  • fingerbob69 - Tuesday, April 05, 2011 - link

    "*nm should read 28nm. Reply
  • jabber - Tuesday, April 05, 2011 - link

    Yeah I feel the 5XXX series were a major improvement that probably did far better than AMD expected, especially as they are still largely an attractive buy, two years later.

    So I saw the 6XXX series as merely a refresh of the 5XXX series. I was in no hurry to buy.

    Hopefully the 7XXX series will be the one to watch out for.
    Reply
  • Hrel - Tuesday, April 05, 2011 - link

    Prices have already "crept up". The GTX460 768MB was available for 130 after rebate for quite a while. Or at least 150 on more expensive brands. Now 150 is the cheapest I can find it. Also, every time you say the GTX460 768MB or the HD6850, if you're getting a 6850 you can get a 1GB GTX 460 for the same price. Just sayin', seems like you're unfairly giving more attention to the AMD product.

    In general though it seems like the GPU manufacturers had a secret meeting where they all got together and decided to start raising prices (profit margins) on all their GPU's. Cause based on performance and past prices the 550ti should be real real close to 100. The 560ti should be basically 200 bucks; 200 is where I'd start recomending that card to people. The GTX460 768MB should be 130 and it should stay there; 1GB should be about 150. And the same can be said for the AMD variants; 6850 would be about 150 and so on.
    Reply
  • Hrel - Tuesday, April 05, 2011 - link

    hmm, just checked prices. Cheapest 1GB 460 I'd buy is 170, gigabyte, cheapest 6850 I'd buy is 155, XFX. So I kinda sorta rescind my statement; but not really. You guys still seem like you root for AMD regardless of who they're compared to. I'm not saying you skew your results and test unfairly; that's why I come here, it just seems like you're all kinda rooting for AMD to get on top in every market. Ofcourse if they did maybe you'd start rooting for Intel and Nvidia... we'll probably never know. Reply
  • H8ff0000 - Tuesday, April 05, 2011 - link

    I know this is unrelated to the article, but does anyone know when AnandTech is going to do some P67 reviews? I'd like to see the Sabertooth P67 Rev 3 reviewed, possibly with some other boards for comparison. Reply

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