Actually dual channel memory is not worth in AMD system.
Single stick of DDR memory already offers matched bandwith..
200MHz FSB and 200MHz DDR memory.. they both work at 2x mode.. so, 400MHz effective.. Also they are all 64bit bus..
nForce is designed for intergrated graphic chipset... That's why the chip is using dual channel memory bus...
You won't get any performance gain even though you are using dual channel memory due to bottleneck between CPU and chipset.
However, nForce offers some small percent of performance gain in dual channel memory. I think the chipset is not optimized under single channel environment..
That's why u get performance gain with dual channel memory..
If single channel memory is highly optimized, there is no reason to go with dual channel memory..
P4 is different... this chip use not DDR, QDR.. Quard Data Rate...!! 4X mode... So, dual channel memory is very important..!!