An Chinese website, IT168, has posted performance results for the unreleased Radeon HD 5830.
The specifications were posted earlier in the week and are as follows acording to a leaked slide that looks official:
Stream Processors: 1120
Texture Units: 56
Memory Bandwidth: 128GB/sec
Power consumpstion: 175W Load, 25W idle
As for the performance, it is approximately 25% slower than the Radeon HD 5850 and hopefully will be priced accordingly. The 5830 chip looks like a part that clocks well but with some of its units disabled compared to the top performing 5870 and slightly less than the 5850.
All in all AMD have just about completed their line up from top to bottom of the 5000 series whilst the NVIDIA DirectX 11 card is still nowhere to be found except announcements on twitter.