If you are utilizing more than 512MB's of system memory at once, you will start to switch banks.. As only one bank of memory can be accessed at a time. Unless of course you are using dual channel memory. So it might be a little faster if you keep the physical switching down between memory slot's. If you just used two sticks you will do more virtual bank switching..
Originally posted by TheMajor
I think 4x512 sticks are faster because of the latencies.
This can be possible.. I would have to take a look at the sticks to see how much difference there is.