Benchmark Results: DiRT 3
At 1920x1080, the Radeon HD 7870 outperforms the 7950, strangely enough. Even at 2560x1440 the two cards finish very close together.
Meanwhile, the Radeon HD 7850 is just barely beaten by the older 6970 at 1920x1080. Push resolution to 2560x1440, though, and the Radeon HD 7850 drops to the point where even a GeForce GTX 560 Ti beats it. Clearly, something is very wrong there.