Performance in RPG
This round is a tie, actually. Both titans of 3D graphics cope with delivering comfortable performance at every resolution but the Radeon HD 4890 CrossFireX system is somewhat slower than its opponent in terms of bottom speed at 2560x1600.
Judging by the results, the multi-GPU technologies are not really called for in this game because it runs fast enough even on a Radeon HD 4890 or GeForce GTX 285 at the highest display resolution.
The Radeon HD 4890 CrossFireX tandem is barely ahead of the ordinary Radeon HD 4870 X2 notwithstanding the higher GPU and memory frequencies, but provides somewhat more comfort at 1920x1200 thanks to the higher bottom speed. The latter is 25fps, which means the lack of any reserve, as opposed to the GeForce GTX 285 SLI subsystem that has a bottom speed of nearly 40fps. The GeForce GTX 295 is somewhat worse in speed but better in usage, so this card is actually the best choice for playing Mass Effect.
None of the multi-GPU solutions can provide a playable bottom speed at 2560x1600 but the GeForce GTX 285 SLI is close to doing that. Subjectively, the game is playable on that platform with a reduction in gameplay smoothness in the most action-heavy scenes.