What is RAM?

Random-access memory, or RAM, is one of the most important components in all devices, from PCs to smartphones to game consoles. Without RAM, doing just about anything on any system would be much, much slower. On the flip side, not having enough for the application or game you’re trying to run can bring things to a crawl or even prevent them from running at all.

But what is RAM exactly? In a nutshell, it’s an extremely fast component that temporarily stores all the information a device needs right now and in the near future. Accessing information in RAM is insanely fast, unlike slower hard drives, which provide long-term storage.

If this is all semantics and you just need to know how to install some RAM or want to find out how much RAM you need, we have guides for that, too.

Short-term memory

RAM is essentially a device’s short-term memory. It temporarily stores (remembers) everything currently running on a device, like all OS-specific services, any web browser, image editor, or game you’re playing.

RAM prevents the CPU from digging through the device’s slower storage — like a hard drive or even a solid-state drive (SSD) — every time you request a new browser tab or load a new enemy to shoot. As fast as storage is compared to drives of years gone by, they’re still far slower than RAM.

Data that resides in RAM can be read from any capable component at almost the same speed. Because it has a hard-wired connection to the device, there’s no real latency in cabling or connection.

RAM doesn’t remember everything forever, however. It’s a “volatile” technology, meaning that once it loses power, it forgets everything. That makes it perfect for handling the multitude of high-speed tasks that your device throws at it each day.

But it’s also why storage systems like hard drives and SSDs are required. Unlike RAM, they hold information when the device powers off.

Bill Roberson/Digital Trends

Different types of RAM

RAM is a bit of a catch-all term, like “memory,” and actually covers a few different types.

“RAM” or “memory” typically refers to dynamic random access memory (DRAM), or more accurately for modern systems, synchronous dynamic random access memory (SDRAM). The terminology doesn’t really matter beyond technicalities, but it’s useful to know that the terms are relatively interchangeable colloquially.

The most common type of RAM sold today is DDR4, though older systems may use DDR3 or even DDR2. The numbers simply denote the generation of RAM, with each successive generation offering faster speeds through greater bandwidth — a higher megahertz (MHz) rating. Each generation also has physical changes, so they are not interchangeable.

Another common term, especially in the video game space, is VRAM, or video RAM. Although once a stand-alone piece of technology, VRAM is currently used to denote dedicated memory on the graphics card. For game consoles, it can also reference system memory, but in either case, it has to do with memory reserved exclusively for the GPU. It’s most commonly referred to as graphics DDR, or GDDR, usually with a generational designation, like GDDR6.

Most modern graphics cards use GDDR6. However, some graphics cards may use a different form of VRAM called High Bandwidth Memory (HBM, HBM2, and HBM2e). It has unique performance advantages although it is typically expensive, and supply issues hinder widespread adoption.

Size isn’t everything

The biggest consideration when buying RAM for a PC is how much is really needed. A minimum amount is required to run an operating system, while many games and applications have a minimum requirement too. Those requirements are listed in gigabytes (GB) and are often between 1GB and 8GB, depending on the application’s hardware demands.

Having more than the minimum is important. A PC runs not only the current application but other services and tasks in the background. However, having massive amounts of system memory doesn’t necessarily make a PC run faster.

The amount is not the only aspect of RAM that’s important. While more gigabytes can help with multitasking, faster memory brings better improvement in overall speed, in certain games, and in applications.

Like a CPU, RAM has its own clock speed, which effectively controls how much data it can handle per second when combined with a few other factors. The total speed of the memory is discussed as bandwidth, in megabytes per second (MB/s), but traditionally you’ll see memory marketed with speeds in megahertz (MHz).

Typical DDR4 memory runs between 2,133MHz and 3,000MHz but there are some that can run upwards of 4,866MHz for the fastest kits available. You’ll see these marketed as DDR4-2133 or similar, and sometimes with the confusing “PC” label. The number following “PC” is simply the MHz speed multiplied by eight and then rounded. For example, you might see it listed as DDR4-2133 PC4-17000.

Timings are another aspect of memory that can have an impact on RAM performance, although they are no longer as important. It’s effectively the time between clock cycles, and as memory speed increases, timings increase as well, reducing latency. Typically, timing is listed as several numbers separated by dashes, such as 15-15-15-35, or similar.

When buying memory, timings are only really important when considering high-performance memory for benchmarking or top-tier gaming. Timing isn’t of real concern to the average consumer.

Lastly, we have channels. Most memory sticks sold today support dual-channel at the very least, which means there are two lanes (buses) between one memory slot and the CPU’s memory controller on the motherboard.

However, this design requires two sticks of RAM of the same type and speed that support dual channels. High-end RAM kits with three or four modules supporting triple- or quad-channel memory designs on motherboards are available as well.

For practical purposes, multi-channel designs don’t make a huge difference in everyday performance. If you do want to take advantage of dual or more channel memory, however, be sure to install the sticks in the correct colored slots on the motherboard. Check the manual for help on that front.

How important is RAM?


RAM is extremely important. Too little can lead to sluggish performance, though smaller devices like tablets and smartphones don’t need as much as high-end gaming desktops. However, installing massive amounts or using the highest MHz rating doesn’t mean a device will run blazingly fast. Remember, RAM is only part of the overall equation.

Having enough RAM does matter, however, and having RAM that isn’t bargain-basement slow is a good idea too, especially for complicated image or video editing tasks and playing games that are CPU-limited.

But when it comes to improving a PC’s overall performance, consider the costs involved. A faster CPU or graphics card will typically make a bigger impact on the overall speed than faster memory. However, some CPUs, like AMD’s Ryzen line, do benefit more than others from faster memory.

Upgrading from a hard drive to an SSD is also a big step in the right direction. The move to an SSD speeds up the slowest storage component by a huge margin and contributes massively to making a PC feel more snappy.

As with any computing device, the slowest component typically limits performance, so slow memory can hold the device back if it’s the worst part of the configuration. Unless you’re doing anything particularly intensive, just be sure to have a little more than what is needed and that it’s not the worst available.

For something more powerful, there is a wide array of configurations of speed, size, and latency to choose from. Some even have RGB LED lighting, too, as shown above.

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