SLI vs. CrossFire, Part 1 – mid-range multi-GPU scaling & value
Serious Sam Second Encounter HD (2010) 
Serious Sam is the title of a series of first-person shooters created by the Croatian development team Croteam. It follows the adventures of its hero Sam “Serious” Stone and his fight against the forces of the extraterrestrial overlord Mental who seeks to destroy humanity. Its gameplay is a throwback to early first-person shooters like Quake and Doom with the twist of being set in wide-open environments with large groups of enemies attacking at any time, and there are many hidden areas and treasures to find and puzzles to solve. Serious Sam features cooperative gameplay and allows for split screen action supporting up to 4 players.
Serious Sam: The Second Encounter was remade as “HD” using Serious Engine 3. It was released on April, 2010 for PC. Besides updated visuals, new game modes including “Co-op Tournament” and “Survival” for single player, were introduced in this remake. Serious Sam 3 is currently in development by Croteam and is expected to debut at E3, 2011. We use the basic 3 “ultra” presets for benching Serious Sam: The Second Encounter HD. There is possible further fine-tuning which will make the game even more demanding, but we chose the “ultra” presets with only one higher GPU setting, to allow for testing beyond 1920×1080. We test first at 2560×1600 resolution:
And finally at 1920×1200 with the same ultra presets:
Serious Sam: The Second Encounter HD on the Serious 3 engine is quite demanding and yet all of our top configurations play it satisfactorily using the game’s built-in “ultra” presets. Although the GTX 560 Ti trades blows with the HD 6870, the HD 6950 is a bit faster and the stock GTX 580 simply blasts past them all. However, GTS 450 SLI is not even sufficiently powerful enough to play this game at our chosen resolutions and level of detail although GTX 460 SLI is able to manage even 2560×1600 even though the single GTX 460 chokes there.
The Radeons are similarly benefited by running them in CrossFire and although they do not scale particularly well; the HD 6870s in CrossFire can run at 2560×1600 while a single card cannot. GTX 560 Ti SLI edges a single GTX 580 at 2560×1600 and is much faster at 1920×1200.
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.