SLI vs. CrossFire, Part 1 – mid-range multi-GPU scaling & value
Just Cause 2
Just Cause 2 is a 2010 sandbox-style action video game by Swedish developer Avalanche Studios and Eidos Interactive and is the sequel to the 2006 video game, Just Cause. Just Cause 2 employs the Avalanche Engine 2.0 which an updated version of the engine used in the original and there are impressive visuals as it is made just for DX10. It is set on the fictional tropical island of Panau in Southeast Asia. Rico Rodriguez returns as the protagonist who aims to overthrow the evil dictator “Baby” Panay and also to confront his former boss, rogue agent Tom Sheldon.
The game play is similar to that of its predecessor in that the player is free to roam the huge open world without a need to focus on the storyline. The Just Cause 2 AI has been rewritten to use a planning system which enables the in-game enemies to do more and there is also more vertical game play as well as a manual aiming system that allows the player to target enemy NPC’s specific limbs. Just Cause 2 also includes an adaptive difficulty system which scales as the player progresses. There are also new weapons in Just Cause 2 which include launching laser-controlled rockets as well as several new vehicles including a Boeing 737. Just Cause 2 even includes dual-grappling hooks which give players the ability to tether unlimited objects to each other including the tethering of enemies to vehicles and to each other which works very well as one of your goals is to cause maximum chaos. It is a lot of fun!
Here are the maximum settings available to a GeForce card; the bottom two, the Bokeh Filter and GPU water simulation, are unavailable to Radeons and they are left off on all runs to give solid apples-to-apples comparisons for all of our tested video cards and we used the Dark Tower benchmark built into the retail game. 
First the benches at 2560×1600 with 2xAA:
The HD 5870 beats the GTX 480 which in turn edges out the GTX 570 but the GTX 580 is solidly faster than any of them. Here the HD 6870 beats the GTX 560 Ti just as HD 6870 Crossfire beats the SLI’s 560s. Although GTS 450 SLI is too weak to play, GTX 460 SLI is faster than the GTX 580.
Now let’s look at the performance at 1920×1200 but now with 8xAA:
The GTX 580 scores an impressive win over the reference GTX 480 with the GTX 570 close behind and the GTX 560 Ti sits in between the HD 6950 and HD 6970. This time CrossFired HD 5870s score nearly perfect scaling to pass HD 6870 CrossFire which in turn is faster than GTX 560 Ti SLI. Both GTX 460 and GTX 560 TI also score some good scaling in SLI and each setup has no trouble surpassing the fastest single video cards. GTS 450 SLI scales well to make this game almost playable; something this budget card cannot dream of by itself at our chosen settings.
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.
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.
why don’t they add BF:BC2?
and also 6950 n 6970 crossfire?
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.
Excellent work! At the end, simple recommendations would have been nice. =)
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.
Civilization 5 has been added to my benching suite along with DiRT 3 and Total War, Shogun 2.
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.