Since high-speed DDR brings some problems, it's only natural to look for ways of increasing the bandwidth of lower-speed DDR. The latest solution is to adopt a dual-channel bus to system memory, thereby doubling the potential bandwidth without having to increase memory clock speeds much higher than normal. This is a good solution to the bandwidth problem, since vendors can use JEDEC-authorized specifications yet still achieve higher-than-DDR400 data transfers. If you look at benchmarks, a dual-channel configuration is about 1-5 percent faster on average. Some specific system benchmarks may go as high as 15 percent.

With an Althon XP processor you will not gain any advantage from dual-channel DDR400 due to the limited bandwidth of the Athlon XP's front side bus (3200MB/second), however a memory controller can never operate at 100 percent efficiency, so you will actually get a memory bandwidth that is noticably lower than 3200MB/second for a single-channel DDR400 configuration. Dual-channel will eliminate most of the loss caused by the memory controllers inefficiency, so that's why you do get a slightly higher memory bandwidth in a dual channel configuration.