Call of Juarez
Call of Juarez does not support 2560x1600 resolution, so we have to limit our tests to 1920x1200.
The average frame rate of the Radeon HD 4870 X2 is lower than that of the Radeon HD 4870 CrossFire configuration but the bottom speed is almost the same. It means you can play the game comfortably at resolutions up to 1600x1200/1680x1050 pixels. Considering that Call of Juarez uses advanced rendering techniques, we can expect the Radeon HD 4870 X2 to be even faster after its Sideport interface is unlocked.
Call of Duty 4: Modern Warfare
The Radeon HD 4870 X2 has a higher bottom speed than the Radeon HD 4870 CrossFire, especially at 2560x1600 where its larger amount of graphics memory seems to be the crucial factor. The ATI solution is only 6% slower than the GeForce GTX 280 but this makes no difference. Both cards can be used to play the game at 2560x1600 with 4x MSAA.