Ahh, I get you.
What I ment was that when the CPU FSB and RAM FSB is not in sync with each other, you will get a slight degrade in system performance, even if the memory is running faster. Hence the reason I asked why he is using 500MHz RAM unless he is overclocking.
The advantage of lower latency times is also pretty expensive for the speed gains. something like a rediculous 2% memory bandwidth increase and overall next to no system performance increase.
Anyway, get Dual channel memory, definatly faster, and increases performance a lot more than getting faster than PC3200 memory for your set up.
If your not overclocking, and your system has a 400MHz FSB, get 2 sticks of PC3200 memory. Cheaper than the PC4000 that would provide no benifit.
If you are planing to overclock then do get the faster PC4000 memory, still dual channel though.