Frankly, we weren't expecting much from Tomb Raider. Our opinion of the game changed once we actually played it, though. Our best description of this title is a mix between an older Tomb Raider game and J.J. Abrams' TV series, Lost. It can be particularly demanding, but we were still able to test the game using its Ultra detail preset (albeit with DoF and HDAO scaled back to the normal settings).
Interestingly, the Radeon HD 6870 falls behind in this title. The Radeon HD 7790 and GeForce GTX 650 Ti tie, achieving very playable results. However, they're bested slightly by the GeForce GTX 560 and significantly by the Radeon HD 7850.
Diving into the frame rate over time shows us that the GeForce GTX 650, Radeon HD 7770, and Radeon HD 6870 struggle to stay above 30 FPS, while the other cards trend higher than 40.
Analyzing the variance between consecutive frame times shows AMD's Radeon HD 6870 posting the worst result, though 8 ms isn't egregious enough to cause an issue.