What is RAM?

Jon Martindale

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. 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 your PC needs right now and in the near future. Accessing that information in RAM is insanely fast, unlike slower hard drives, which provide longer-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 your device’s short-term memory. It temporarily stores (remembers) everything that runs on your PC, like all the services in Windows, your web browser, your image editing tool, or the game you’re playing. You don’t want the CPU digging through your 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 the short-term memory, or RAM, can be read from anywhere at almost the same speed. Because it has a hard-wired connection to your system, 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 system throws at it on a daily basis. But it’s also why we need storage systems like hard drives and SSDs, which actually hold our information when you turn the system off.

Different types of RAM

RAM is a bit of a catch-all term, like “memory,” and actually covers a few different types. Most of the time when people discuss RAM or memory, they’re technically referring to DRAM (dynamic random access memory), or more accurately for modern systems, SDRAM (synchronous dynamic random access memory). 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 memory on the graphics card. In games consoles, it can also reference system memory, but in either case, it has to do with memory that is 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, though it is typically expensive, and supply issues hinder widespread adoption.

Size isn’t everything

The biggest consideration when buying RAM is how much you need. 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, or GB, and are often between 1GB and 8GB, depending on the application’s hardware demands.

Having more than the minimum is important, as your device runs not only the current application but other services and tasks in the background. Of course, having massive amounts of system memory doesn’t necessarily make your device faster either.

The amount is not the only aspect of RAM that’s important. While more gigabytes can help with multitasking, you can see better improvement in your device’s speed, in certain games, and in applications through faster memory. 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, but traditionally you’ll see memory marketed with speeds in 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, though 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 if you’re considering high-performance memory for benchmarking or top-tier gaming. Timing isn’t of real concern to the average consumer.

Lastly, you should know about channels. Most memory sold today supports 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 supports dual channels. You can also find high-end RAM kits with three or four modules that support triple- or quad-channel memory designs on motherboards.

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

How important is RAM?

G.Skill

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 your 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 your system’s overall performance, you need to consider the costs involved. A faster CPU or graphics card will typically make a bigger impact on your system’s overall speed than faster memory, though 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 if you haven’t taken it yet. The move to an SSD speeds up the slowest storage component on your system by a huge margin and contributes massively to making it feel more snappy.

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

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