The Ultimate Guide to Random Access Memory

You’d find it in pretty much any computer or smartphone, be it a desktop to a laptop to a hand-held device, if not all of the above. It’s a robust, high-gain, and high-speed solution that provides applications, operating systems and games instant priority access to important information. It saves it the trouble of finding and retrieving data stored on a slower drive, such as a hard drive. Even the fastest SSDs endure a much slower span of time compared with RAM.

But, like other components inside all your devices, there are many different kinds of RAM. The speed of your RAM can depend on its type, its model, or its generation. Its price differs dramatically based on how much you’re buying (assuming you know how much your PC/laptop/game console/phone needs), and what you’re putting it into.

What is RAM, and what does it do?

RAM is a device’s short-term memory. It reads the information, either from an application or an operating system, that it deems might be needed for the next millisecond, and puts it there temporarily to be used by the CPU or the graphics card, or any other component to which it might be needed. That information stays in the RAM as long as you are running the program, or as long as the device is working and you are using it before it eventually gets refreshed. Once the program is closed or the device is rebooted, the RAM is empty and ready to be filled with new, relevant, information.

Much like the cache on a CPU, RAM keeps other components from having to seek the device’s slower storage (in this case, the hard drive, or even a solid-state drive [SSD)], every time you open a new browser tab or unleash a new enemy to shoot. For all the rapid progress of storage, even the fastest storage today is hundreds if not thousands of times slower than RAM. But those components are needed all the same, because they’re the long-term storage of the data when away.

What are the different types of RAM?

The more popular term is ‘RAM’, but what is usually meant is dynamic random access memory (DRAM) or more accurately, in modern systems, synchronous dynamic random access memory (SDRAM). The right term doesn’t matter in most contexts beyond technological ones, but the point here is that the terms are colloquially relatively interchangeable.

You probably know that we sell RAM for computers, and chances are the most popular RAM we sell (and most desktop computer RAM sold today) is DDR4. If your computer is older, it might have DDR3 or even DDR2 RAM, and if it’s newer it might be DDR5 RAM. The DDR part stands for Double Data Rate and, as the last number in the name indicates, this is the fourth generation of RAM (the first, second and third generations being SDRAM, DDR, and DDR2, respectively). Each generation provides an increase in speed over the generation before through higher bandwidth (aka megatransfers per second). Each generation has physical changes as well, and tends to use less power than the previous generation, so they are not interchangeable.

Every mobile device such as a laptop, tablet or cellphone uses LPDDR memory, available in LPDDR 4 generations and, most recently, LPDDR5X. Generally the performance is similar to desktop-grade DDR, albeit a little less – though not quite as fast as the highest-end of DDR5. It uses about the same power, too, but draws less so it saves on battery. They also come in different form factors, sometimes soldered to the motherboard, or DIMM (Dual In-line Memory Module) but with the S in front, standing for Small Outline, because they are much smaller than the sticks used in full-size DIMM that attach to desktop PCs.

A second related term, still very common in the video game space, is VRAM (video RAM). Originally a stand-alone component of systems, it was then used to distinguish memory on the card dedicated to the graphics signal, and today we sometimes see that meaning used interchangeably in discussions around game consoles, where the system memory is also sometimes referred to as VRAM. In all cases, though, where memory is explicitly distinguished as V(ideo)RAM, it refers to a specific portion of memory assigned fully to the GPU.

Currently, pretty much all our high-end PC gaming GPUs, such as AMD’s new RX 7000-series, use GDDR6. Not so with GDDR6X, the slightly faster memory that currently graces only Nvidia graphics cards, such as its RTX 3000 and RTX 40-series.

But, the next generation of GPUs will use GDDR7 VRAM which I believe is still in the making.

How much RAM do you need?

Every operating system, every game or every application runs with a specific amount of RAM, and will run better with more, so you need to ensure you have enough. For most people this is between four gigabytes (GB) and 16GB, with 8GB being the minimum for any modern PC running Windows. Most modern gaming PCs will have 16GB, but some modern AAA games can benefit from having 32GB. Anyone doing a lot of video editing or heavy multi-tasking will want either 32GB or more.

You definitely want more than the bare minimum quantity of RAM. A PC runs much more than the current application; it also runs a wide variety of other services and background tasks, but forking out for huge quantities of system memory won’t make your PC run any faster and, once you’ve got a sufficient amount, the faster or better quality the memory the better.

Do you need fast RAM?

And memory, like a CPU, has a clock speed. In conjunction with a couple other factors, the speed of your memory determines how much data it can move every second – this is referred to as bandwidth and measured in megatransfers per second, although you’ll still see memory advertised in megahertz (MHz).

Common DDR4 memory operates somewhere between 2,133MHz and 3,000MHz – with some of the fastest out-of-the-box kits topping out at 4,866MHz or so – while in DDR5 memory that number can go as high as 8,000MHz with some kits. Generally, you’ll see this marked as DDR4-2 [whatever] or something similar: often, the speed can be a little confusing with some vendors using that baffling ‘PC’ label. The number listed after ‘PC’, if you need to check, is simply the MHz speed you’ve chosen multiplied by eight and rounded off. So if you see something like DDR4-2133 PC4-17000, that’s where you look.

Memory timings are another issue that affects RAM performance – though nowadays they’re much less important. A set of timings is usually given as a string of numbers separated by hyphens, like 15-15-15-35 or something similar. Each of the numbers (loosely speaking) refers to the number of clock cycles between certain points of the controller and memory communication. Generally, as memory speed increases, so do the timings, and latency goes up as a result – but at a certain point, the greater bandwidth presents more than enough benefit to cancel out the added latency.

Timings only become a consideration when buying memory if you’re going to use it for benchmarking or high-end gaming. Otherwise, they’re not really of any concern to any consumer.

What are RAM channels?

Nearly every memory stick sold today supports at least dual-channel, which means there are two lanes – known as buses – between the memory slot and the memory controller on the motherboard that connects to the CPU. For dual-channel to work, you have to install the two accompanying memory sticks in the right colour slot on the motherboard. If your motherboard has a manual, refer to it to see the colour for dual-channel, and the correct use of the slots.

High-end RAM kits with triple- or quad-channel memory designs on motherboards are available, though they are typically found in workstations and server systems. Usually, such memory arrangements are implemented through a combination of three or four independent modules rather than one single big one.

Can you get more RAM without upgrading?

Unfortunately, no. Many jokes sites will claim that this is possible and that you can ‘download’ some more RAM, but unfortunately there’s no way to get more memory unless you install some. On the other hand, if you’re constantly running out of memory, shut down any open applications (especially browser tabs) that might be using your memory to help free up some.

Reducing the memory pressure further, you could also turn off the startup programme that determines which apps start up with the operating system on your PC: if you never spend time staring at your hard drive icon in frustration because you know that your computer is ‘just not fast enough’, then the fastest discussion will have little impact on your productivity or your quality of life.

How to install RAM?

And now that you’ve learnt all about RAM, are you ready to install some yourself? Check out our tutorials on how to upgrade your PC’s RAM and how to upgrade your laptop’s RAM.