Enabling Dual Channel (Intel and AMD Socket AM3+)
Motherboards targeted to Intel CPUs and AMD socket AM3+ CPUs (and a few socket AM3 models) use sockets one and two as the first channel, and three and four as the second channel. In order to enable the dual-channel architecture, you have to install one module at the first channel and one module at the second channel. If they are installed in the same channel, you will have a single-channel architecture. Therefore, you must install the first memory module in socket one, and the second memory module in socket three, not in socket two. In other words, you have to skip one socket.
In order to make it easier for users, most motherboard manufacturers use different colors on the memory sockets, using one color for sockets one and three, and a different color for sockets two and four. This way, you need to install the memory modules in sockets with the same color. See Figure 5.
In Figure 6, you can see a motherboard for an Intel CPU with two memory modules correctly installed, enabling dual-channel architecture.
There is, however, one major exception. On some older motherboards from MSI targeted to Intel CPUs, sockets one and two use the same color while sockets three and four use another color. See Figure 7. If you install the two memory modules in sockets with the same color on a motherboard like this, they will work under single-channel mode, not dual-channel. So, if you find yourself in front of an older motherboard from this manufacturer, you should not follow the color scheme. You must install the memory modules in sockets one and three, and they will be using sockets with different colors.
If you are installing four memory modules which are identical, there is no rule to follow. Simply install all four modules in the four sockets available.
However, if you are installing four modules and they have different capacities, you will have to pay attention. The first pair must be installed in sockets one and three, while the second pair must be installed in sockets two and four. By “pair” we mean two identical memory modules. In other words, install the first pair in sockets with the same color, and the second pair in the sockets using the other color.