You want to use the motherboard with DDR3 to triple channel the RAM in order to increase performance. When you open your computer, you notice that four RAM slots are available. How can you use the increased performance of triple channel with four slots available?

The memory speeds (clock rates), maximum capacity per memory module, total maximum capacity, and types (DDR, DDR2, DDR3, etc.) that a system can accept is defined by the memory controller. For example, if a given memory controller only supports DDR3 memories up to 1,333 MHz, you won't be able to install DDR2 memories, and if you install DDR3 memories above 1,333 MHz (e. g., 1,866 MHz or 2,133 MHz modules), they will be accessed at 1,333 MHz. (An exception to this rule is when the motherboard allows you to configure the RAM at a clock rate above the official maximum supported by the memory controller. For a real example, current Intel CPUs support memories up to 1,333 MHz, but several motherboards will allow you to configure clock rates up to 2,133 MHz.)

The dual-, triple-, and quad-channel architectures work by increasing the number of data wires available in the memory bus, doubling, tripling or quadrupling the available bandwidth, respectively.

It is very important to notice that this performance increase is achieved only on the memory subsystem; doubling the theoretical memory performance does not translate into a computer that is twice as fast. Only a small percentage of this memory performance increase will be reflected on the overall system performance.

Let's now examine exactly how each of those architectures work and how to enable them

Check the motherboard documentation to find which modules are supported. Purchase additional modules that are the same as what is currently installed.