Half-Life 2: Episode Two
We used a custom-recorded timedemo for this game, as well. We tested Episode Two with the in-game image quality options cranked, with 4X AA and 16 anisotropic filtering. HDR lighting and motion blur were both enabled.

Episode Two is a very different scaling story for CrossFire X and three-way SLI. Adding a third GeForce 8800 Ultra is a performance detriment, while going to three and even four GPUs benefits the Radeon HD 3870. Here's the tough question, though: why? Two GeForce 8800 Ultras are faster than four Radeon HD 3870s. The fact that each 3870 GPU is slower means there's more potential headroom for CrossFire X to scale. That said, the results at lower resolutions seem to indicate AMD is doing a better job than Nvidia of managing three (and four) GPUs without running into CPU bottlenecks or the like.

In this game, we should note, CrossFire X is only needed at 2560x1600 resolution. Below that, at 1920x1200, quite a few single- and dual-GPU solutions are plenty fast. Also, notice that three-way CrossFire X is only a hair faster than two GeForce 9600 GTs in SLI—a much less expensive option.