MultiGPU Update: Does 3-way Make Sense?

Fallout 3 Analysis

Even with iPresentInterval set to 0 and vsync disabled, Fallout 3 has an LOD system that limits performance to certain averages. The frame rate can and does go beyond 60, but when it gets to a certain point it drops back down to below 60 in a sort of sawtooth pattern. This can make getting useful comparison data tough especially when we start adding higher and higher performance options to the mix.

1680x1050    1920x1200    2560x1600

As we can see, some two GPU solutions do better than the 3-way options, especially at lower resolutions. Again, at 2560x1600, the 512MB per GPU 3-way configurations struggle to keep up. With Fallout's performance profile, it's a safer bet to run a single card with a good amount of RAM or at most a two way setup as we just don't need more power for this one.

1680x1050    1920x1200    2560x1600

Because of the LOD limited performance, we see speed up with 3 GPUs from 1 at only about 50% out of a possible 200%. In the worst case, at high res with a low memory part, we can even see performance degradation. The GeForce GTX 260 stands out at high resolution, while the 9800 GTX+ and 4850 put in a good showing at lower resolutions.

1680x1050    1920x1200    2560x1600

Failure is the word that comes to mind when looking at scaling up from 2 to 3 GPUs. There isn't a single case where the extra GPU helps improve performance in a significant way at any resolution. There is just no reason for 3 GPUs with Fallout 3.

1680x1050    1920x1200    2560x1600

Our value data bares this out with the 3-way solutions clustered at the bottom of our list. The GeForce GTX 280 and 285 SLI options are still pretty abysmal in delivering on framerate for your money as well. The only boost we see in value comes in at 2560x1600 for 3-way options that have more than 512MB of RAM. The only reason these cards show better value though is because some configurations fail to perform adequately to play the game at this resolution.

Bottom line is that 3-way is unnecessary for Fallout 3 from a performance standpoint, doesn't produce any significant benefit over 2-way options, and is a horrible investment all around for this game.