Dual channel Question

So me and my friend are having an arguement.

Mobo Layout :

[Chan1] [Chan2] <---------------------> [Chan1] [Chan2]

Okay the above is the MOBO layout; one of us says dual channel = having 2x512mb on the Left side (occupying chan 1 and 2). The other one says dual channel = having 2x512mb on the same channel # , ie both on chan 1. Whos right?

 

If you want two identical sticks of RAM to operate in dual channel mode on a motherboard that supports dual channel operation, you place them in the slots with the like-colored retention clips. Typically, the docs will say put the two sticks in slots 1 and 2, but the slots are really laid out 1 - 3 ---- 2 - 4. Like I said look for the color-coded clips.

 

Too achieve dual channel you need one chip in each channel.
If both chips were in the same channel it wouldnt be dual channel!

Dual Channel = two

MOBO manufactures color code thier mem slots, but each can be different.
Example: I have Asus A7N8X Deluxe 2.0 one channel is marked black the other is marked blue, for dual channel one chip in black one in blue. one other note this mobo has three mem slots one channel being black the other channel, two slots are blue, for dual channel one black slot & either of the two blue.

I also have Gigabyte dual channel mobo GT 2004, P4, 4 mem slots, this mobo has two purple & two black slots, it's different from the Asus cause each mem channel has one black and one purple slot too achieve dual channel you simply install the two mem chips in the same color slots, if ya have 4 identical mem chips it dont matter.

All mobo manufactures mobo manual's will have info on what slots to use for dual channel.

 

Note Always true regarding the color of the slots, read my previous post.

2 cents more:
Some mobos have the slots you use grouped togather, some dont.
You must read the mobo manual and follow that particular instruction