Benchmarks: Street Fighter IV, World in Conflict
The Radeon HD 5830 was 16% faster than the Radeon HD 4890 when running Street Fighter IV at 2560x1600, rendering an average of 92fps. This made it roughly 17% slower than the Radeon HD 5850. For some reason Nvidia cards really struggle with this game, the GeForce GTX 285 rendered just 61fps.
In World in Conflict we see the Radeon HD 5830 fall behind the Radeon HD 4890 for a third time, with an 11% performance margin between the two. The Radeon HD 5830 was only able to match the 4870, and was as much as 20% slower than the 5850 at 2560x1600.