SLI vs. CrossFire, Part 1 – mid-range multi-GPU scaling & value
CRYSIS
Next we move on to Crysis, a science fiction first person shooter by Crytek. It remains one of the most demanding games for any PC and it is also still one of the most beautiful games released to date. Crysis is based in a fictional near-future where an alien spacecraft is discovered buried on an island near the coast of Korea. The single-player campaign has you assume the role of USA Delta Force, ‘Nomad’ who is armed with futuristic weapons and equipment.
Crysis uses DirectX10 for graphics rendering. A standalone but related game, Crysis Warhead was released the following year. CryEngine2 is the game engine used to power Crysis and Warhead and it is an extended version of the CryEngine that also powers Far Cry. As well as supporting Shader Model 2.0, 3.0, and DirectX10’s 4.0, CryEngine2 is also multi-threaded to take advantage of dual core SMP-aware systems and Crytek has developed their own proprietary physics system, called CryPhysics. However, it is noted that actually playing this game is a bit slower than the demo implies. All of our settings are set to the in-game maximum’s “very high” including 2xAA for 1920×1200 and for 1680×1050 and we force 16xAF in the control panels.
Here is Crysis’ Island Demo benchmark, first at 1920×1200 resolution:
Although the HD 5870 passes the GTX 480, the GTX 580 moves right past it. The GTX 570 is a bit faster than our GTX 480 and the GTX 560 is just edged by the HD 6870. All of our cards scale well in CrossFire or SLI beating the single flagship cards except for our GTX 450 which, although it scales OK, is just too weak to play. Next we test at 1680×1050.
The GTX 480 is edged out by the GTX 570 although the HD 5870 is faster. However the GTX 580 is even faster still and the GTX 560 Ti is a bit faster than the HD 6870. The GTS 450 simply cannot manage Crysis at these settings and adding a second one for SLI is barely sufficient for smooth game play. On the other hand, GTX 460 is too weak to play Crysis until we add a second one for SLI. The CrossFired HD 5870s run close in performance to the pair of HD 6870s but the GTX 560 Ti pair is the fastest, easily topping the GTX 580’s performance.
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.