I'm not the best at explaining things.
Back in the days of the Athlon XP, Pentium 4 and even the Athlon 64 cpu's and DDR and DDR2 memory the biggest problem was generating enough Memory Bandwidth. The cpu and memory system was more or less bottlenecked so to speak. Since were limited on the memory bandwidth the best way to increase performance is to decrease the latencies, which makes each read and write request faster.
But today we have the Phenom, Core 2 Duo and the i7 cpu's and DDR3 memory. Compared to the systems of old these setups generated a lot of Memory Bandwidth. And while faster latencies is still good, there just not as necessary because the bootleneck has been virtually eliminated.
Think of it like this. Two years ago when you ate dinner all your plates were only sized for a single serving. So you needed a plate for each food item and they were scattered around you. When you wanted something different you had to pick-up a plate, move it, replace with desired plate.
Today your Plate is supersized and everything fits nicely in one plate. When you want something you just casually fork it and eat it. You no longer need to shift your plates around. And if you do need to grab another plate it's big so you only need to move one, whereas the same task two years ago usually required multiple plates.
I don't know if this helped, but I'm hungry