SLI vs. CrossFire, Part 1 – mid-range multi-GPU scaling & value
FarCry 2
Far Cry 2 uses the name of the original Far Cry but it is not connected to the first game as it brings you a new setting and a new story. Ubisoft created it based on their Dunia Engine. The game setting takes place in an unnamed African country, during an uprising between two rival warring factions. Your mission is to kill “The Jackal”; the Nietzsche-quoting mercenary that arms both sides of the conflict that you are dropped into.
The Far Cry 2 game world is loaded in the background and on the fly to create a completely seamless open world. The Dunia game engine provides good visuals that scale well. The Far Cry 2 design team actually went to Africa to give added realism to this game. One thing to especially note is Far Cry 2’s very realistic fire propagation by their engine that is a far cry from the scripted fire and explosions that we are used to seeing. First we test Far Cry 2 benchmark at 2560×1600 with AI enabled and we use the Ranch Long benchmark with ultra settings plus 4xAA.
Let’s move on down to 1920×1200 resolution while increasing our AA from 4x to 8x.
The GTX 580 and the GTX 480 run away from the Radeons and the GTX 580 is clearly the fastest of the single cards. Here we see a clean sweep by the GTX 580 in Far Cry 2 while the GTX 570 trades performance blows with the GTX 480. The GTX 560 Ti even beats the fastest Radeon, HD 6970 in this game. However, we see CrossFired HD 5870s and HD 6870s score nearly perfect scaling although they are both beaten by GTX 560 Ti SLI. GTX 460 SLI also beats the fastest single flagship video cards while GTS 450 SLI allows this game to be playable whereas a single GTS 450 cannot cope.
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.