OCC has published another review on a 4850 this one being the Sapphire HD4850

The Sapphire HD4850 utilizes ATI's design of their newest core using a 55nm manufacturing technology, the RV770 using 512MB of GDDR3 memory. I had expected to see some great numbers from the new card, however what I saw was way beyond what I expected. The stock benchmarking scores of the HD4850 beat the 9800 a few times and got beat a few times by it, however once the Sapphire HD4850's core was overclocked to 670MHz and the memory was pushed all the way up to 1100MHz, it was able to compete with the competition's newest card, the GTX 280. When the card was overclocked, unlike the PowerColor HD4850, the temperatures of the GPU were sitting around 82-86 degrees Celsius under load, while these temperatures are not very good and are quite high, I felt that they were safe enough for me to be able to run some benchmarks.

Sapphire HD4850 Review