Triple-GPU Scaling: AMD CrossFire Vs. Nvidia SLI

Power, Heat, And Efficiency

So a single GeForce GTX 570 really puts the hurt on a single Radeon HD 6950, while better scaling leads to 6950-based CrossFire triumphs. While we could go on to say that most multi-GPU buyers will be happier with AMD, there’s the little matter of operational expense that we still haven’t considered.

Oops! It might be acceptable for Nvidia’s better-performing card to consume more power in a single-GPU configuration, but CrossFire’s superior performance scaling makes the GeForce GTX 570 a poor efficiency choice in SLI. Note that the power was measured using a game as well as FurMark. This was essential, since the middle Radeon HD 6950 was completely idle during the FurMark test.

The GTX 570s also ran hotter, but this editor would like to note that AMD’s sink design leads to extremely tight fan spacing in 3-way mode. Local banshees abandoned our neighborhood at the commencement of power testing.

With Just Cause 2 (at our maximum test settings) making up the most-important portion of our power test, we used the corresponding benchmark values to calculate full-load efficiency. Average performance and power set the full-load baseline, while average power alone (for all six configurations) set the active idle baseline.

Lower power consumption and better performance gave AMD a big efficiency lead, while excellent performance scaling at a constant cost in CPU power allowed multiple HD 6950s to score higher full-load efficiency than a single card.

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  • Impressive and unexpected results. Speculations that crossfire scaling is worse than SLI can finally be put into rest.
    15
  • Other Comments
  • :( i wish i could afford that
    4
  • wow even though a 6950 is weaker than a 570 it dominates at higher resolutions eyefinity here i come.
    8
  • Impressive and unexpected results. Speculations that crossfire scaling is worse than SLI can finally be put into rest.
    15
  • scrumworksImpressive and unexpected results. Speculations that crossfire scaling is worse than SLI can finally be put into rest.

    Not true, I would have liked to see more games on the test. The choices were too limited for my taste. For example, everyone knows that Crysis is heavily Nvidia favored, so it's not surprising to see those results in the least.

    Here's another article on the 68xx series in Xfire
    http://www.xbitlabs.com/articles/video/display/radeon-hd6870-hd6850-crossfirex.html#sect0

    Xfire scaling was found to be 100% on 10 or the 19 games they tested, and remaining very high on the others. Nvidia and ATi seems to trade blows at different games tested, but it is evident that Ati has stepped up their Xfire drivers int he 6xxx series.
    -2
  • scrumworksImpressive and unexpected results. Speculations that crossfire scaling is worse than SLI can finally be put into rest.

    I misunderstood what you meant. But yes, xfire/sli scaling has improved alot this generation :)
    7
  • Now im thinking if i should even spend on a now older 5850 to crossfire on my X58.
    2
  • Its really cool to see amd stepping up their game. Multigpu scaling used to be only good on nvidia, but now amd is beating them. Though i feel that more games should be tested before a firm conclusion should be drawn.
    5
  • I would get two HD 6870 for a mobile crossfirex gaming rig ! :D
    1
  • No! Don't buy a 5000-series card to crossfire. The 6000 series cards are essentially all better at crossfire scaling than their predecessors. This performance advantage will likely only increase with additional driver revisions and better 6000-series optimization support than for older products.
    1
  • Great review ! It's good to see AMD did a lot of work on CF scaling.
    2
  • I wish you Tom's would have done a 6970 trifire comparison instead. It's on average cheaper than the 570 on the Egg right now. I guess i get the memo, with showing that a cheaper solution is outperforming a more expensive option, but there would have been a good deal of performance increase across the board with the clock speed differences and opened shaders that is the 6970. Those differences come more alive in scaling especially with 3 cards.
    3
  • You can see that AMD knows multicard setups are the future. Now i really want to get my 6950 :)
    1
  • @Thomas:
    You can test eyefinity resolutions on single monitor IF that monitor has 3 inputs. Can you give this a try please?
    0
  • Holy crap! After reading this review, I decided to look into the 6950 cards again.

    If you're in Canada, you can get an XFX 6950 1Gb card for $215.99 (after rebate)right now from NCIX! That's a stupidly amazing deal!!! Think I'll grab one!
    http://www.ncix.com/products/index.php?sku=58455&vpn=HD695XZNFC&manufacture=XFX&promoid=1293
    3
  • Loved the idea of the article. Very disappointed with the display setup. It should go up to 5760x1200.
    3
  • LuayLoved the idea of the article. Very disappointed with the display setup. It should go up to 5760x1200.
    Asus' 25" 1920x1200 display is still well priced, but I don't expect to see them around much longer. You should tell Chris to order three of these for every editor, before that bargain price vanishes!
    2
  • why not test the 6970 and the 570? they are the same price point, the 6950 is one tier lower.
    1
  • Quote:
    Things get ugly for Nvidia at 2560x1600. While a 67% performance gain for two-way and 112% gain for three-way SLI certainly aren't shabby, AMD’s 92% two-way and 245% 3-way gains put it in the winner’s circle.
    Well the graph for nVidia shows 212.11%, so a 112% gain is correct, but the graph for AMD shows 244.87%, so 245% gain is incorrect, that should be 145% gain. Still better then nVidia, but not that much better...
    0
  • "The closest competitor is Nvidia’s GeForce GTX 570" Wrong !

    The closest competitor is the Nvidia`s GTX 560Ti price vs price. At least in my country.
    -6
  • executor2"The closest competitor is Nvidia’s GeForce GTX 570" Wrong ! The closest competitor is the Nvidia`s GTX 560Ti price vs price. At least in my country.
    Could you please show me the GTX 560 Ti model that supports 3-way SLI? I'd love to test those too!
    7