SLI vs. CrossFire, Part 1 – mid-range multi-GPU scaling & value

STALKER_CS

S.T.A.L.K.E.R., Call of Pripyat is the third game in the S.T.A.L.K.E.R. series. All of these games have non-linear storylines which feature role-playing game elements. In both games, the player assumes the identity of a S.T.A.L.K.E.R.; an illegal artifact scavenger in “The Zone” which encompasses about 30 square kilometers. It is the location of an alternate reality story surrounding the Chernobyl Power Plant after another (fictitious) explosion. S.T.A.L.K.E.R., Call of Pripyat features “a living breathing world” with highly developed NPC creature AI.

Call of Pripyat is compatible with DirectX 8, 9, 10 and 10.1. It uses the X-ray 1.6 Engine with dX 11, one outstanding feature being the inclusion of real-time GPU tesselation– a Shader model 3.0 & 4.0 graphics engine featuring HDR, parallax and normal mapping, soft shadows, motion blur, weather effects and day-to-night cycles. As with other engines using deferred shading, the original DX9c X-ray Engine does not support anti-aliasing with dynamic lighting enabled, although the DX10 and DX 11 versions do.

We are using the stand-alone “official” benchmark by Clear Sky’s creators. We picked the most stressful test out of the four, “Sun shafts”. It brings the heaviest penalty due to its extreme use of shaders to create DX10/DX10.1 and DX11 effects. We ran this benchmark fully maxed out in DX11.0 with “ultra” settings plus 4xAA, including applying edge-detect MSAA which chokes performance even further. Here we present our maxed out DX11 settings for S.T.A.L.K.E.R., Call of Pripyat DX11 benchmark with 2xAA at 1920×1200:

Now we move on to 1680×1050 with 2xAA:

The GTX 580 makes a clean sweep of these single card benches although we would still lower settings at 1920×1200 to have a completely smooth playing experience. We see the GTX 560 Ti’s performance sit between the HD 6870 and the HD 6950. Our GTS 450 SLI scales well enough to make this playable over a single GTX 450 although GTX 560 Ti doesn’t scale well enough which allows it to get beat by both CrossFired pairs of video cards. GTX 460 SLI is next performance-wise and it trades blows with the GTX 580 depending on the resolution.

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apoppin

Founder and Senior Editor of ABT.

8 Responses

  1. Bo_Fox says:

    I’m not 100% certain, but to analyze microstuttering, place a check in the box next to “Frametimes” in Fraps. Then when you press the hotkey, it will create a log file with a timestamp when each single frame was outputted. Only a few seconds is enough to make the log file really, really long. Then take a portion out of the log file and make a chart out of it, that measures the time between each timestamp, to see if the frames are consistent with each other in similar intervals, or if every other frame is too close to the other one.

    If a game runs at say, 45fps with your SLI or CF setup, but feels more like 23-30fps, then definitely analyze this with FRAPS.

  2. EP says:

    Great review so far.

    How do the numbers change, if at all, if Split Frame Rendering is used instead of Alternate Frame Rendering?

    The last time I used SLI was with my Voodoo2 3000s. It was a gigantic waste of $200, in 1996 dollars.

    If SFR eliminates micro-stutter without too much of a performance penalty I might have to try SLI again.

  3. Tejas says:

    why don’t they add BF:BC2?
    and also 6950 n 6970 crossfire?

  4. DoktorSleepless says:

    Concerning the microstutter, frames time (using that fraps option) is supposed to fluctuate more erratically on crossfire/sli than what it would be on a single card. I think instead of testing a moving scene, it would make more sense to test it on a completely still scene for a few seconds and see how they compare in the excel output file. You don’t want a moving scene because then you won’t be able to differentiate between the erracticness you would get from a moving scene and the erraticness you would get from microstutter.

    Another interest option would be to downclock a sli/crossfire setup to a point where it matches the average framerate of the single card. This way you could could see if the multi-gpu setup looks choppier than a single card despite having the same average frame rate.

  5. Justin says:

    Excellent work! At the end, simple recommendations would have been nice. =)

  6. bbb_forever says:

    Please include Civilization 5 if possible the next time you benchmark.
    It is an important game which will test the tesselation feature and its scaling ability in multi-gpu configurations.

  7. apoppin says:

    Civilization 5 has been added to my benching suite along with DiRT 3 and Total War, Shogun 2.

  8. ltwally says:

    You’ve done a great job of benchmarking gaming performance, but including charts with FPS vs $$, and $$ vs wattage would be much more useful.

    The wattage (both idle and load) figures can be especially important, as some of these cards can easily draw more juice than all but the most powerful (and expensive) power supplies can provide — and that definitely factors into the cost analysis.

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