Our Summary and Conclusion
Performance Summary: In terms of their designs and specifications, the Sapphire Radeon HD 4850 X2 and GeForce GTX 280 / 285 couldn't be any more different. But in terms of performance, the cards couldn't be more evenly matched. The GeForce GTX 280 / 285 and Radeon HD 4850 X2 basically traded victories throughout testing, depending on the game, application, or resolution used.
We're a bit torn regarding the Sapphire Radeon HD 4850 X2. On one hand, the card offers excellent performance, a decent bundle, and a solid feature set, that includes quad DVI outputs. And its price is right about where it should be in the current 3D graphics market, which is to say it is priced slightly higher than a reference clocked GeForce GTX 280 at about $330. There are a couple of issues with the Sapphire Radeon HD 4850 X2 that take away some of its luster though. The extra-long >11" PCB may pose a problem in some cases (like the one we used for our reference system) and the card may simply not fit in some systems. We also found the dual-fan cooler to be somewhat loud in comparison to the similarly performing GeForce GTX 280 and 285 series cards--although not by much. Consumers must also consider than dual-GPU powered cards like the Sapphire Radeon HD 4850 X2 are limited by driver constraints that single-GPU powered cards are not. Typically, if a single-GPU powered card that offers similar performance is available for about the same price as a dual-GPU powered card, we'd recommend the single-GPU powered card every time to eliminate the potential hassles. We should note, that cards like the Radeon HD 4870 X2 and GeForce GTX 295 have the same driver-related performance constraints on them as well, but there are no single-GPU powered cards that can outperform them.
In the end, the Sapphire Radeon HD 4850 X2 is a solid performer with some interesting features. Just be aware of the potential issues we've pointed out if you're in the market for a graphics card of this type. If it's within your budget and you may make use of the additional outputs, the Sapphire Radeon HD 4850 X2 isn't likely to disappoint.