Multi-Channel Memory Guide
Your computer performs best when you use all the memory channels available on your motherboard. Blue Iris software in particular can show a significant reduction in CPU usage when changing from a single-channel memory configuration to a dual-channel memory configuration.
What is dual-channel memory?
(or single-channel, quad-channel, etc?)
Most modern computer motherboards support at least dual-channel memory, and it is important to understand what this means when you want to maximize your hardware's potential.
The terms
"single-channel",
"dual-channel", and
"quad-channel" describe how computer memory is accessed by the CPU. Do not mistake these terms for different kinds of RAM (a.k.a. computer memory).
Memory is just memory. For example, if you buy a "dual channel kit", you are just buying 2 memory modules of the same model/speed/size. There is no such thing as a "dual-channel memory module".
Whether your computer is using a single, dual, or quad-channel memory configuration depends on the capabilities of the motherboard and how the physical memory modules were installed.
What Memory Configuration Do I Have Now?
If you do not have an appropriate number of memory modules (a.k.a. RAM sticks) installed, or if they are in inappropriate slots, it is possible that your system is running fewer memory channels than it is capable of.
There is a program called HWiNFO which can tell you what your memory configuration currently is. Get it here:
https://www.hwinfo.com/
How to Correctly Install a Multi-Channel Memory Configuration
Choose an appropriate number of RAM sticks
First, you should obtain your RAM in multiples of the number of supported memory channels. For example if you have a dual-channel motherboard (extremely common in 2019), you can start with 2 RAM sticks. Or 4 RAM sticks if your motherboard has 4 RAM slots (also extremely common). It would not be optimal to install 1 RAM stick or 3 RAM sticks. Use the same size and speed (ideally the exact same model) of RAM in each slot, for best performance and reliability.
I'm not filling all slots; which should I use?
It is common for a computer to have 4 RAM slots, but only support a dual-channel memory configuration. In this situation, you can get away with installing only 2 RAM sticks without a performance penalty. The manual for your motherboard will tell you which slots to use. If you can't find the manual, the rule of thumb is to use the 1st slot nearest to the CPU, then skip one slot and fill slot 3, so you leave slots 2 and 4 empty. This is because the first two slots are typically for memory channel A while the second two slots are for memory channel B, and you want one memory stick on the same side of each channel.
Here is a brief guide with pictures explaining how to install memory in a dual-channel configuration:
https://www.hardwaresecrets.com/everything-you-need-to-know-about-the-dual-triple-and-quad-channel-memory-architectures/5/
Other configurations (triple-channel, quad-channel, etc)
For motherboards where the maximum memory channels is 3, 4, 8, etc, the same principles apply as for dual channel. Install the memory in multiples of the number of memory channels, and consult the motherboard manual to find out which slots to use.
