SLI vs. CrossFire, Part 1 – mid-range multi-GPU scaling & value
DiRT 2
Colin McRae: DiRT 2 is a racing game that was released in September 2009, and is the sequel to Colin McRae: Dirt. It includes many new race-events, including stadium events as your RV travels from one event to another in many real-world environments across four continents. Dirt 2 includes five different event types even allowing you to compete at new locations. It also includes a new multiplayer mode.
Dirt 2 is powered by an updated version of the EGO engine which was featured in Race Driver: Grid. This updated EGO engine also features an updated physics engine. We are using the Dirt 2 full retail game built-in benchmark at the highest “ultra” DX11 setting with 8xAA applied. First we test at 2560×1600:
The GTX 580 pulls ahead and passes the second place GTX 570 and third place GTX 480 in a not so tight race. The GTX 560 Ti is just edged by the HD 6950. We see HD 6870 CrossFire scale a bit better than HD 5870 CrossFire but not enough to catch it in ultimate performance although they both beat GTX 460 SLI which moves past the GTX 580. What about 1920×1200?
The GTX 580 gets the DiRT 2 checkered flag on the DX11 pathway as the GTXes pull further away from the Radeons at 1920×1200. However, even the lowest priced HD 6870 can play this game satisfactorily at the highest resolutions and we see the GTX 570 pull ahead of the GTX 480. The GTX 560 Ti again sits in between the performance level of the HD 6970 and the HD 6950 in this game. GTS 450 SLI makes this game playable for our lowest performing pair of cards and our GTX 460 SLI scales very well but not enough to catch the GTX 580 this time although GTX 560 Ti is much faster.
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.