What Is RAM and What Does It Do?

Random Access Memory, or ‘RAM’ for short, is super-fast memory that stores data temporarily for active programs.

Updated 22/05/2024

When discussing the internal workings of computers, one of the most crucial components to understand is random access memory (RAM). In this blog, we’ll delve deep into what computer RAM is, why it’s important, and how upgrading RAM can boost your system’s performance. Whether you’re a gamer, designer, or just an ordinary user, having a better understanding of RAM will help you make a more informed decision when shopping for memory at ebuyer. Let’s get started.


  1. What is Computer RAM?
  2. The Importance of RAM and Why RAM is Necessary
  3. RAM Frequency vs RAM Latency: How RAM Performance is Determined
  4. DDR RAM Explained
  6. What Else to Consider When Buying RAM
  7. RAM at ebuyer

What is Computer RAM?

Random access memory, often referred to as just ‘memory’, allows data to be accessed by the processor (CPU) as fast as possible, maximising performance. You can think of memory as the middle-man between your computer’s CPU and its storage devices. RAM is fast – faster than even a top-of-the-range solid state drive. When you open a program, it’s not loaded straight off the storage device. This would be too slow. Instead, essential data for running the program is temporarily transferred over to memory. This ensures that the CPU has access to the data it needs at a moment’s notice, rather than going to and from a relatively slow storage device. Without memory, even the simplest task on your computer would be unbearably slow. Consequently, the more memory a computer has, the more efficiently it can handle multiple tasks and resource-intensive programs.

RAM is Volatile

RAM is what’s known as ‘volatile’ memory, meaning it requires power to keep hold of the data that’s stored on it. Unlike long-term storage devices, which retain data even when they’re powered off, any data stored in memory will be wiped clean when you shut down your computer. So while RAM may be ultra-fast, it’s only used for short-term, temporary storage. Hard drives and solid state drives, on the other hand, will retain your data on a long-term, permanent basis.

Memory vs Storage: What’s the Difference?

Memory is not the same as storage, though we can see why it’s easy to conflate the two. While they may sound interchangeable, memory and storage perform very different roles in a computer. In short, memory (RAM) is fast but volatile, whereas storage (HDD, SSD) is non-volatile but comparatively slow. To reiterate, when you open a program, its data is transferred from storage to memory. Then when you close a program, its data is saved back to storage for safe keeping. Since it’s volatile, RAM is used only as a temporary workspace for the processor.

The Importance of RAM and Why RAM is Necessary

System Stability

Everything on your computer requires RAM to function. It doesn’t matter if it’s a memory-hungry triple-A game or a small background process sitting in your system tray – it all consumes RAM. You need to make sure you’ve got enough RAM in your computer. Otherwise, a computer will resort to substituting storage for memory in a process called ‘paging’ or ‘swapping’. When this happens, it’s not a good time. As storage is much slower than memory, running off this virtual memory will degrade performance and result in slowdowns, freezes, and sometimes outright crashes.

OS Efficiency

The operating system itself requires memory to function properly. Common OS-related tasks like managing resources, processes, and caching frequently used data all rely upon there being available RAM. Insufficient RAM can lead to the rest of the computer bogging down as the operating system struggles to allocate resources efficiently.


Each program consumes a portion of memory to store its instructions and data for the CPU to execute on. So by equipping a PC with more RAM, you allow it to run more programs simultaneously. The more memory a computer has, the more data it can keep readily available. This reduces the need to swap data in and out of slower storage devices, which would otherwise decrease efficiency and performance. As a result, having a large amount of memory is important for those who like to multi-task between multiple programs.

While the amount of RAM needed varies from user to user depending on their use cases (as detailed thoroughly in our blog How Much RAM Do You Really Need), it’s recommended to have a bit more than the bare-minimum recommended amount. If, for example, a new game requires 8GB of RAM, it’s generally a good idea to have 16GB of RAM to account for everything else running in the background of a system. This could include voice-over-IP software like Discord, a browser with many tabs open, and the operating system itself. Having this extra memory headroom will help ensure a smoother, stutter-free computing experience.

Fast Access to Data for CPU

CPU themselves feature a small amount of ultra-high-speed memory called cache. Cache serves the same purpose as RAM: to give the CPU near-instant access to data. However, there’s only so much cache that can be squeezed onto a CPU due to their size. For example, even with its impressive 3D-stacked cache technology, the AMD Ryzen 7 7800X3D still only has 96MB of L3 cache. This is only enough to hold the most essential of data. RAM is like an extension of this cache for all your other data, even if it is a bit slower since it has to travel across the motherboard.

RAM Frequency vs RAM Latency: How RAM Performance is Determined

The relationship between RAM frequency and RAM latency is crucial for understanding memory performance. RAM frequency describes that rate at which data can be transferred to and from a memory module. On most sites, including ebuyer, it’s measured in MHz (megahertz). At higher frequencies, more data can be moved in a given amount of time, leading to faster performance. RAM latency, on the other hand, describes the time delay between when a command is issued to RAM and when the data actually become available to use. It’s measured in clock cycles and is usually represented by a CL (CAS Latency) value: CL14, CL16, and so on. Lower CL values mean lower response times and, in turn, better performance.

Strike a Balance for Optimal Performance

Ideally, you’d want both high-frequency and low-latency RAM for optimal performance. However, it’s common for there to be a trade-off between the two. Sometimes, higher frequency memory modules may have slightly higher latency, and vice versa. So having extremely high frequency RAM won’t necessarily translate to better performance if its latencies are too high. Even if the on-paper transfer rate is fast, the delay in accessing the data can negate any performance advantage. Conversely, RAM with lower latency can compensate for lower frequency by providing much quicker access to data. In some cases, PCs with lower-frequency, lower-latency RAM may outperform those with higher-frequency, higher-latency RAM. So while both frequency and latency are important, it’s crucial to strike a balance between the two. When shopping for RAM, don’t just look at frequencies at the top of the product description – scroll down further to see its latencies, too.

DDR RAM Explained

When shopping for memory modules, you will come across DDR4 and DDR5 RAM. DDR stands for Double Data Rate, a technology used in memory modules to improve performance. As the name implies, DDR allows data to be transferred twice per clock cycle, effectively doubling data transfer rates compared to older, now-obsolete SDR (Single Data Rate) RAM. There are several generations of DDR RAM, each bringing improvements in speed, bandwidth, and efficiency.

  • DDR1: The first generation of DDR RAM, introduced in 2000. DDR1 RAM operated at 100-400MHz with a maximum bandwidth of 3.2 GB/s.
  • DDR2: Released in 2003, DDR2 RAM improved upon DDR1 RAM by offering up higher speeds, ranging from 400-1,066MHz, and increased bandwidth up to 8.5GB/s. It also brought lower operating voltages for better power efficiency.
  • DDR3: Introduced in 2007, DDR3 further increased speeds, ranging from 800-2,1333MHz, with higher bandwidth up to 17GB/s. Continuing the trend of lower operating voltages, DDR3 offered better power efficiency than DDR2. DDR3 was supported for a long time; you may find an older system still rocking DDR3 RAM.
  • DDR4: Released in 2014, DDR4 brought significant advantages in both speed and efficiency. It offered speeds ranging from 1,600MHz to 3,200MHz and beyond (with potential for even higher speeds via overclocking) and increased bandwidth up to 25.6GB/s. DDR4 operates at even lower voltages than DDR3, contributing to improved power efficiency and heat dissipation. Many PCs to this day use DDR4 RAM; it’s fast enough for most all while being extremely affordable. Newer AMD Ryzen 7000 Series-based systems only support DDR5 RAM, however.
  • DDR5: The latest generation of DDR RAM, introduced in mid-2020. DDR5 RAM offers super-fast speeds, starting from 4,800MHz and hitting up to 8,000MHz, resulting in significantly increased bandwidth compared to DDR4. DDR5, like the generations before it, also boasts improved power management for enhanced efficiency. While AMD has fully embraced DDR5, Intel still offer motherboards with support for either DDR4 RAM or DDR5 RAM. Naturally, DDR5 will result in the best performance.

Importantly, each generation of DDR RAM is not designed to be backward compatible with the previous generation. You cannot, for example, install a DDR5 RAM module in a motherboard with a DDR4 RAM slot. Upgrading to a newer generation of DDR RAM brings with it a noticeable improvement in performance, especially in memory-hungry programs and bandwidth-starved workloads.


There are two different form-factors of memory modules. DIMM (Dual In-Line Memory Module) is the standard form-factor used in desktops, servers, and high-performance workstations. It’s a full-sized form-factor featuring a longer, rectangular shape with pins on either side of the module. Since it’s larger than SO-DIMM, DIMM is typically used in roomier, stationary systems. SO-DIMM (Small Outline Dual In-Line Memory Module) is used in laptops, mini PCs, all-in-one PCs, and other compact systems where space is at a premium. Compared to DIMM, SO-DIMM is smaller, stubbier, and only has pins on one side of the module. While both DIMM and SO-DIMM modules serve the same purpose in a computer, their different sizes affect compatibility. It’s important to be able to distinguish between DIMM RAM And SO-DIMM RAM so you can ensure compatibility with your system’s motherboard. Over at ebuyer, we break RAM down into three different categories: Laptop RAM (SO-DIMM), Desktop RAM (DIMM), and Server RAM (DIMM again).

Image: Shutterstock

What Else to Consider When Buying RAM

Single vs Dual-Channel Configuration RAM

Where performance is concerned, it’s better to install multiple DIMMs of RAM in a system, as opposed to just one. When RAM is ran in a dual-channel configuration (i.e. two DIMMs), your processor’s memory controller will access data from both modules at the same time, effectively doubling bandwidth. It’s for this reason that RAM is usually sold in ‘kits’ of two or more ‘sticks’ (memory modules). If you’ve got the choice between a single 16GB stick of RAM or dual 8GB sticks, for example, go for the latter to ensure optimal performance.

CPU Cooler Compatibility

Lastly, one factor you probably won’t have considered is the height of the RAM, but it’s essential to check that a memory module’s heatsink (if it has one) isn’t too tall. Otherwise, the memory module may not be able to fit underneath your computer’s CPU cooler, blocking installation. So when shopping for RAM, don’t just look at its frequency and latency. You must keep in mind its height too, ensuring that both the RAM and CPU cooler will fit together nicely.

Image: Shutterstock

RAM at ebuyer

Now that you understand what RAM is and why it’s so important, why not treat yourself and your PC to a much-needed RAM upgrade? You’ll find all the different types of Ram you’ll need right here at ebuyer. Head over to our Desktop RAM, Laptop RAM, and Server RAM pages to do some browsing of your own and discover your next RAM upgrade. But remember to refer to this guide so that you get everything spot-on.

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