One of the most important elements in computer performance is RAM. It stores open programs, files, and even parts of the operating system. Therefore, when upgrading your computer, upgrading the RAM is often one of the primary options. It's somewhat inexpensive and brings considerable speed improvements.

However, a few questions may arise when updating RAM. One is whether it's better to have it all in a single slot or to use multiple modules, known as single, dual, and sometimes quad-channel memory.

What Are RAM Channels?

Most motherboards have a couple of slots or more for RAM modules. Some laptops may feature soldered memory alongside a free slot (and some only use embedded RAM that can't be upgraded). Still, at least a single space for upgrades is usually available. Desktops often have four or more of those.

When only one memory slot is used, the RAM runs in a single-channel configuration. That means all the provided RAM comes from the same place—that slot.

But computer processors can access RAM from multiple slots at the same time. That's what multi-channel RAM means: having RAM modules installed in more than one of the available spaces.

If two slots are used, that's a dual-channel setup. If four are in use, it's quad-channel. Triple channel, which has—you guessed right—three slots occupied, is less common but also a possible configuration.

For example, the motherboard pictured above has four RAM slots (the long, vertical white lines in the center-left). If this motherboard supports a maximum of 64GB RAM, each RAM slot likely supports a maximum 16GB RAM module. If that is the case and a user attempts to install two 32GB modules (to reach the 64GB RAM limit), the computer will only recognize 16GB for each slot or, even worse, not work at all.

However, that isn't a universal rule. Different motherboards support different amounts of RAM per slot. For example, you may find another motherboard with four slots and a 64GB RAM limit that supports 2x32GB or 4x16GB RAM modules. The only way to truly know is to check the motherboard specs before buying or upgrading your RAM.

Also, note the generation of RAM dictates the maximum amount of RAM per slot. Motherboards using DDR4 RAM are limited to 64GB per slot because that is the maximum DDR4 module size. If you have a DDR5 motherboard, that figure rises to 256GB per module.

More Memory, Faster Memory, or More Channels?

That leads to the questions: Should you use more memory in a single-channel configuration, and what are the situations in which having multiple, smaller RAM modules is better?

The answer depends on two factors: 1) how much you're willing to spend, and 2) what are the performance bottlenecks in your computer.

The first one is because, no matter what computer you have, purchasing a single 16GB module is almost always less expensive than buying two 8GB ones. The chips in a 16GB module are more expensive, but two 8GB ones mean the manufacturer had twice the cost with components like heat sinks, packaging, and shipping. And these costs will be passed on to you, the final customer.

The difference may be small, depending on how you use your machine. Regular RAM modules for office computers, e.g., will only be a few bucks apart on a single vs. dual-channel comparison. On the other hand, performance memory for gaming PCs or professional uses like video editing will have a more pronounced difference.

Usually, having multiple modules with less RAM is better because the processor will be able to access all of them at the same time. Since each channel is read/written separately, it's faster to do that on two 8GB modules operating side by side than a single 16GB one because the read/write speed will be doubled.

Talking about speed, we get to the second point. If the read/writing rates aren't important in your setup, you're better off with fewer but larger modules—that'll save you some money. On the other hand, if you're looking to maximize performance, multi-channel is the way to go.

The video below shows how far the difference goes for games. Using the exact same graphics settings for all the titles tested, a dual-channel setup had at least 10-15% higher frame rates, sitting at 20-25% most of the time. In some cases (notably Watch Dogs 2), the frame rate doubled.

But, even if you want the fastest possible option, if your motherboard or CPU isn't up to the game, even a quad-channel configuration won't help much. It will probably still be faster than single-channel, but the difference won't be as perceivable. So check your whole setup before purchasing so you don't waste money.

There's also the option of buying faster memory modules instead of larger ones. If you're upgrading from entry-level RAM to high-end RAM in a single purchase but can't or don't want to use a multi-channel configuration, check the frequency of your current memory and the maximum supported by your motherboard, as investing in faster RAM could give a performance bump similar to using multiple slots.

How to Use More Memory Channels

After the explanation above, the question remains: how to best use the memory channels? Here are a few tips. We'll stick to dual-channel examples to make things easier to follow, but the following points apply to triple and quad-channel setups.

First and foremost: if possible, always use modules from the same manufacturer with the same capacity and speed. While this helps because you'll know that all of your memory has been bought to work in unison, it isn't a strict rule; it's one of many common myths about RAM.

If that's not an option, try to keep the modules' specs as similar as possible, as every RAM module will run at the same speed as the slowest module. For example, if you have two RAM sticks and one runs at 2,400MHz RAM but the other runs at 2,133MHz, the whole setup will be slowed down to 2,133MHz automatically.

Modules with different capacities are also common. Bought a laptop with 8GB of RAM but later had the cash to get a 16GB module for the other slot? Things won't run optimally, but they won't be terrible, either.

Here's what happens in this scenario: of the full 24GB (8GB + 16GB) available, 16GB (8GB from the original module plus 8GB from the new one) will work in a dual-channel configuration. The remaining 8GB from the second module will also be usable but slower because this portion will run at single-channel speeds. The motherboard and the operating system work in confluence to detect this kind of setup automatically and will prioritize the dual-channel part of your RAM whenever they can. The single-channel portion will only be used if there's no faster memory available.

This tech is called hybrid dual-channel or asynchronous dual-channel. For Intel processors, this is known as RAM Flex Mode. AMD CPUs also support this feature, but AMD doesn't give it a specific name. However, remember that this configuration isn't recommended for systems demanding high performance, like gaming PCs, because RAM-intensive tasks may not always play well with hybrid dual-channel setups.

Different RAM for Different Needs

RAM management can get tricky. When the principles are explained, however, things are way simpler.

For those on a tight budget or with other bottlenecks, get fewer but larger RAM modules. Dual or quad-channel RAM is better if you can spend more money on a faster computer.

Just remember: RAM isn't the only possibility for performance improvements. Getting faster storage like NVMe SSDs, or a CPU with higher speeds and more cache could be a better investment than upgrading your memory.