Motherboards published a Diamond ATI Radeon HD 4850 review. Diamond just announced the HD 4850 Card last Friday.

Quote from the review: "This card will essentially be a XFX Black Edition 9800GTX as the clock speeds will be 738MHz for the core and higher clock speed for the Shader clock. It will be an interesting battle for sure, but ATI has fired the first salvo towards high-performance sub-$200 video cards of 2008. The high-end enthusiast market wanting an ATI card that competes well against NVIDIA's best will have to wait a month or so until the HD4870 arrives and its dual-chip brother the 4870X2. They will have higher clock speeds, GDDR5 memory and be much more competitive against the GTX260 and GTX280 (here's a hint; two 4870s working together on a single PCB will likely outperform GTX280 for the same price point) If this forces NVIDIA to lower their prices it will be a much better market, after all, who wants to spend $650+ on a new video card if you can help it.
The 4850 does what it is designed to do with high end performance outclassing the HD3870 across the board for a $200 price point using less power and with excellent features the HD4850 is interesting competition to NVIDIA's mid-range card the 9800GTX+ and 9800GTX standard at $199."
Read the full review on Motherboards.