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Sapphire Toxic HD 7970 GHz Edition Review: Gaming On 6 GB Of GDDR5

Clock Frequencies And Power Consumption: Gaming

We used the same three clock rates on the previous page for our gaming analysis: 1100 MHz (from the factory), Lethal Boost's 1200 MHz, and a static 1201 MHz.

The TDP-based frequency limiter didn’t kick in at all in our gaming workload, maintaining 1100 MHz and Lethal Boost's 1200 MHz. Part of this is due to Sapphire's aggressive cooling profile, which also makes the Toxic HD 7970 GHz Edition 6 GB quite loud.

One interesting attribute of Lethal Boost is that it extends the PowerTune limit to 50 percent instead of 20. Thus, we added this as another variable to test. Set to 50 percent, the card started jumping between 1100 and 1200 MHz. So, we fixed the clock rate at 1201 MHz.

Power consumption jumps quite a bit from 1100 MHz to the higher frequency settings. At 1100 MHz, we recorded about 204 W. The 1200 and 1201 MHz settings were a little higher, at 218 W. Stepping up to the 50 percent PowerTune setting increased consumption to 229 W.

Does this affect frame rates at all?

The higher frequencies barely make a difference in frame rates (at least, not enough to justify up to 20 percent more power consumption). Really though, this is the same thing we saw in our review of Gigabyte's Radeon HD 7970 Super Overclock. Taking Tahiti over 1100 MHz is simply inefficient. PowerTune doesn’t help in these scenarios either. In fact, it's counterproductive at the highest setting. The feature pushes maximum frame rates higher as minimum frame rates drop, yielding noticeable stuttering.

  • Youngmind
    The 6gb of memory might not have much of an effect with only a single card, but I wonder if it will have a larger impact if you use in configurations with more graphics cards such as tri-crossfire and quad-crossfire? If people are willing to spend so much money on monitors, I think they'd be willing to spend a lot of money on tri/quad graphics card configurations.
    Reply
  • robthatguyx
    i think this would perform much better with a trifire.if one 7970 reference can handle 3 screens than 3 of these could easily eat 6 screen,in my op YoungmindThe 6gb of memory might not have much of an effect with only a single card, but I wonder if it will have a larger impact if you use in configurations with more graphics cards such as tri-crossfire and quad-crossfire? If people are willing to spend so much money on monitors, I think they'd be willing to spend a lot of money on tri/quad graphics card configurations.
    Reply
  • palladin9479
    YoungmindThe 6gb of memory might not have much of an effect with only a single card, but I wonder if it will have a larger impact if you use in configurations with more graphics cards such as tri-crossfire and quad-crossfire? If people are willing to spend so much money on monitors, I think they'd be willing to spend a lot of money on tri/quad graphics card configurations.
    Seeing as in both SLI and CFX memory contents are copied to each card, you would practically need that much for ridiculously large screen playing. One card can not handle multiple screens as this was designed for, you need at least two for a x4 screen and three for a x6 screen. The golden rule seems to be two screens per high end card.
    Reply
  • tpi2007
    YoungmindThe 6gb of memory might not have much of an effect with only a single card, but I wonder if it will have a larger impact if you use in configurations with more graphics cards such as tri-crossfire and quad-crossfire? If people are willing to spend so much money on monitors, I think they'd be willing to spend a lot of money on tri/quad graphics card configurations.
    This.

    BigMack70Would be very interested in seeing this in crossfire at crazy resolutions compared to a pair of 3GB cards in crossfire to see if the vram helps in that case
    And this.

    Tom's Hardware, if you are going to be reviewing a graphics card with 6 GB of VRAM you have to review at least two of them in Crossfire. VRAM is not cumulative, so using two regular HD 7970 3 GB in Crossfire still means that you only have a 3 GB framebuffer, so for high resolutions with multiple monitors, 6 GB might make the difference.

    So, are we going to get an update to this review ? As it is it is useless. Make a review with at least two of those cards with three 30" 1600p monitors. That is the kind of setup someone considering buying one of those cards will have. And that person won't buy just one card. Those cards with 6 GB of VRAM were made to be used at least in pairs. I'm surprised Sapphire didn't tell you guys that in the first place. In any case, you should have figured it out.
    Reply
  • FormatC
    Tom's Hardware, if you are going to be reviewing a graphics card with 6 GB of VRAM you have to review at least two of them in Crossfire.
    Sapphire was unfortunately not able to send two cards. That's annoying, but not our problem. And: two of these are cards are deadly for my ears ;)
    Reply
  • tpi2007This.And this.Tom's Hardware, if you are going to be reviewing a graphics card with 6 GB of VRAM you have to review at least two of them in Crossfire. VRAM is not cumulative, so using two regular HD 7970 3 GB in Crossfire still means that you only have a 3 GB framebuffer, so for high resolutions with multiple monitors, 6 GB might make the difference.So, are we going to get an update to this review ? As it is it is useless. Make a review with at least two of those cards with three 30" 1600p monitors. That is the kind of setup someone considering buying one of those cards will have. And that person won't buy just one card. Those cards with 6 GB of VRAM were made to be used at least in pairs. I'm surprised Sapphire didn't tell you guys that in the first place. In any case, you should have figured it out.Why not go to the uber-extreme and have crossfire X (4gpus) with six 2500X1600 monitors and crank up the AA to 4x super sampling to prove once and for all in stone.
    Reply
  • esrever
    The normal 7970s seem much better than the ghz edition.
    Reply
  • freggo
    FormatCSapphire was unfortunately not able to send two cards. That's annoying, but not our problem. And: two of these are cards are deadly for my ears
    Thanks for the review. The noise demo alone helps in making a purchase decission.
    No sale !

    Anyone know why no card has been designed to be turned OFF ( 0 Watts !) when idle, and the system switching to internal graphics for just desktop stuff or simple tasks?
    Then applications like Photoshop, Premiere or the ever popular Crisis could 'wake up' the card and have the system switch over.

    Or are there cards like that ?


    Reply
  • FormatC
    For noise comparison between oc'ed Radeons HD 7970 take a look at this:
    http://www.tomshardware.de/Tahiti-XT2-HD-7970-X-X-Edition,testberichte-241091-6.html
    Reply
  • dudewitbow
    freggoThanks for the review. The noise demo alone helps in making a purchase decission.No sale !Anyone know why no card has been designed to be turned OFF ( 0 Watts !) when idle, and the system switching to internal graphics for just desktop stuff or simple tasks?Then applications like Photoshop, Premiere or the ever popular Crisis could 'wake up' the card and have the system switch over.Or are there cards like that ?
    I think that has been applied to laptops, but not on the desktop scene. One of the reasons why I would think its not as useful on a desktop scene is even if your build has stuff off, the PSU is the least efficient when on near 0% load, so no matter what, your still going to burn electricity just by having the computer on. All gpus nowandays have downclocking features when its not being on load(my 7850 downclocks to 300mhz on idle) but I wouldnt think cards will go full out 0.
    Reply