This is an interesting quote from the conclusion of the HardOCP review of the 7950:
http://www.hardocp.com/article/2012/01/30/amd_radeon_hd_7950_video_card_review/15
Quote:
Troubled Games and CrossFireX
AMD still has its work cut out with CrossFireX drivers. We've encountered two games here that do not seem to do well with Radeon HD 7950 CrossFireX. Batman was the worse, the performance was unusually slow with Radeon HD 7950 CrossFireX, possibly indicating immature drivers for a game that was released in November of 2011. Skyrim also performed rather poorly in comparison, also a title released in November of last year. NVIDIA has a leg up on AMD with Skyrim multi-GPU performance. Of course, NVIDIA also had SLI support for Skyrim months before AMD had any CrossFireX support in the game.
There is always an aspect of gameplay performance that is hard to relate to gamers through a graph, or even words. We are talking about physically "feeling" a game as you play it. What people perceive as playable performance is not always attached to framerate. This seems to be a fact of CrossFireX that we've encountered in our gameplay testing. At times, the framerate being displayed on the screen doesn't match what we are "feeling" as we play the game.
For example, if 40 or 50 FPS is indicated, even though that should be playable since its above 30 FPS it won't necessarily feel playable. We have to shoot for higher FPS. We experience some kind of lag or choppiness in gameplay with CrossFireX even though the framerate indicates it should be playable. This means you cannot always rely on framerate alone to determine playable performance.
This is a difference that separates CrossFireX from SLI. With SLI we do not experience this phenomenon as much. With SLI, framerates seem smoother at lower framerates, than these do with CrossFireX. For example, we often find we need to aim for higher framerates in order for CrossFireX to feel like it’s playable. Whereas, with SLI we often find we can settle with lower framerates, because it feels playable at those framerates. Trust us, we do not go by framerates when evaluating how these cards actually game. The framerates lie.
Some of this can be seen in the graphs, when we talk about consistency. We've shown it in this evaluation, look back at the Deus Ex or Skyrim graphs and you will see SLI producing a more consistent framerate. These are just facts between CrossFireX and SLI, but it makes it so that SLI feels smoother and better to us, than CrossFireX does often. This was the case a lot of the time testing Radeon HD 7950 CrossFireX versus GeForce GTX 580 SLI. We just felt GeForce GTX 580 SLI offered a smoother experience, in pretty much every game, even the ones where Radeon HD 7950 CrossFireX allowed higher in-game settings.