Overclocking of the cards was pretty decent. Both of the cards were able to increase both the GPU Core and Memory clocks by about 20% over the stock speeds, which is no small feat. The pricing on both of the cards is quite competitive. However, with the price only being $20 apart from each other, I would suggest the Sapphire HD5850 Xtreme over the Sapphire HD5830 Xtreme. You are going to see better results. About a 20% higher score in 3DMark 11 at the 2560 x 1600 resolution at stock speeds.