AnandTech has compared some AMD 890GX, Intel X58 and Intel P55 based motherboards to find out which platform delivers the best SATA 6Gbps performance. You can check out the article over here, looks like the AMD 890GX delivers some pretty good performance:
AMD’s ATI acquisition was about bringing graphics to the portfolio with the eventual goal of integration into the CPU itself. We’ll see the first of that early next year with Llano. But as AMD goes down this integration route, it needs to make sure that its chipsets are at least up to par with Intel’s. Many have complained about AMD’s South Bridges in the past, but with SB850 we’ve actually seen some real improvement. There still appear to be some strange behaviors and I don’t like that there’s any discrepancy between AMD’s reference board and retail 890GX boards, but these results look very promising.