A question about DDR2 RAM....

[Crian]

There's single channel, and dual channel, right? Could anyone knowledgeable on this please explain the difference between the two? And under which setups are they best?

I want to get more RAM for my comp but I want this clarified first before I do anything, thank you.

[Lemur]

When available, dual-channel is always better. Basically, hrm, what's the easiest way to explain ...

Your CPU is very, very fast. The channel it uses to talk to the RAM is slow by comparison. Any tricks the motherboard can use are helpful; dual-channel architecture is such a trick. It accesses pairs of RAM as, well, two channels instead of one.

I'm having a hard time putting this simply. Here's a primer on how dual-channel works. Trust the wiki, not the lemur.

[LeftEyeNine]

Trust the Wiki, and the Lemur.

P.S. Dual DDR means double bandwidth availability as you insert two identical DDR RAM modules, instead of a single one.

[Husar]

How about four modules? Can they run in Dual-Channel mode as well?
I'm thinking about one of those new mainboards with four slots and four times 1GB modules, would that result in two modules sharing one channel or so?

[Lemur]

How about four modules? Can they run in Dual-Channel mode as well?

As long as they are installed in matched pairs, there's no reason not to run them dual-channel. But as far as the mobo and CPU are concerned, it will still be a situation with two channels, not four.

[Crian]

I... sort of understood the wiki... Thanks for the reply Lemur... I was getting suspicious about my system underperforming.

So in my current setup (sig), my RAM is effectively causing a bottleneck in my system, is that right? I want to upgrade to 2 GB DDR2 667 dual channel, and those would be the ones labeled with "(2 X 1GB) DDR2"... right? OR is it simply sticking in 2 sticks and tweaking the BIOS?

EDIT: Oh and do I need some special setup in my motherboard to get this to work? Or do you just plug this in like most RAM sticks? And do I have to set this up in the BIOS or will it automatically run itself dual channel? My board has 4 DDR2 memory slots.