look at the benchmarks between S754 and S939 setups. A 754 CPU at the same clock will perform about the same as a 939. A64's do not have a memory bottleneck using dual or single channel memory from the benchmarks I have seen, and from own personal use. Try it yourself, run FRAPS in dual and single channel mode, and you will see for yourself. Regardless of that info though, I would still recommend dual channel for peace of mind, and I am sure in some cases it will make a difference.