It doesn't matter, and won't for a long time. The fastest bus speed I'm hearing of for the future is 800MHz (QDR400) and Intel already has a chipset in testing that supports dual channel DDR400 for it. You don't need more bandwidth fpr the memory bus than for the CPU bus, it's mostly just wasted!
<font color=blue>You're posting in a forum with class. It may be third class, but it's still class!</font color=blue>