Dual Channel question

[WingWizard]

Okay, I have a simple question....how exactly does dual channel work? I currently have a 512 mb stick of GEIL pc3200 @ 418MHz, and according to Sandra I get a score of around 3000. I've seen other reviews and what not (of corsair, mushkin, etc.) in 2x256mb dual channel having a score of around 5000+; what's the deal? Will adding another 512 mb stick in dual channel bump up my memory bandwidth?

Thanks!

[Manfordjinsen]

You have to have 2 identical sticks of ram installed to use the dual channel option on a dual channel ddr motherboard, so by adding another 512 stick of ram would up your sandra memory scores alot. I know on asus motherboards you have to have the ram installed in specific slots to use dual channel ddr so it could be like this on other boards too.

[Telexen]

RAM is traditionally written to the modules one at a time...when one fills up, the next (if available) takes over any new memory needed to be stored.

With this dual channel memory, it can write to two different modules at once, so it writes a block of memory to one module, and the next block to the other. Since both channels can be accessed and written to at one time, memory is theoredically twice as fast...though it's not...but there's still a big increase.