RAM or Random Access Memory serves as a “water tank” of the system, where the processor stores the necessary data to keep the system running. Below is diagram of the role of system memory.
As long as you don’t need massive amounts, RAM will be among the cheapest of the system’s essential components of. It is also the easiest to buy, with just a few things to keep in mind. Keep reading our suitably simple guide to get tips on how to buy RAM for your new system.
RAM/Memory Types
When buying memory for a new system, you need to take a look at the motherboard’s memory compatibility, whether it is DDR4 or DDR5. You can only put specific types of memory modules (also known ass memory sticks) in the RAM slot of the motherboard.
First, make sure to look for the right generation of RAM, e.g. DDR4 or DDR5. These are not compatible as they have different specs and pinouts:
Memory Capacity
As mentioned earlier, memory serves as a “water tank” for data. It is very important that your system has adequate memory capacity to accommodate all the necessary files and data to keep the system running at optimal level without slowing down. Otherwise, it will start swapping to your SSD, which will reduce performance.
By today’s standards, 8 GB is enough for basic tasks like internet browsing, office works, and watching movies. For gaming, 16 GB is the minimum, and 32 GB for workstations.
Memory Speed and Data Rate
Before the introduction of Double Data Rate Technology (DDR), RAM speed is measured in Megahertz (MHz, this is also the RAM’s clock speed). Back then, RAM can only transfer data once per cycle, so the MHz label directly corresponds to the speed of the RAM. RAM with an 800 MHz label meant a speed of 800 million clock cycles (operations) per second.
But when DDR was introduced, data transfer was doubled without increasing the clock speed. The DDR RAM running at 800 MHz could suddenly transfer data at 1,600 million operations per second. This effective transfer rate of data is also known as megatransfers per second, or MT/s, which is a more accurate way of expressing DDR DRAM speed.
The MT/s label is rarely used as it creates confusion to consumers used to MHz label as basis of the RAM’s speed. Both MT/s and MHz are representation of RAM speed – the higher the number the faster. But when comparing RAM speed, be careful not to compare the MT/s of the module to the MHz of another module.
Before buying RAM modules, check the motherboard’s maximum supported overclocked RAM speed. Buying RAM running at a lower rate won’t give you problem, but you will not be able to maximize the available speed for your system unless you know how to overclock (and if the RAM will allow it). Higher ratings won’t give you problems either, but you will be spending more for nothing. If your motherboard can only support a maximum of 6400 MT/s and you use 7000 MT/s RAM, your memory will still run at 6400 MTs.
CAS Latency
Column Address Strobe Latency (CAS or CL) is the delay in time between receiving the data request from the CPU to when the RAM begins delivering it. The RAM needs to locate the address of the requested data after receiving the request, and that’s when the delay happens. The lower the latency (shorter delay), the faster the memory delivers the data. This can make the system somewhat less prone to stuttering in games.
RAM with higher MT/s or MHz usually have higher CL value, meaning higher latency. RAM at the same MT/s with lower CL value will perform better because it responds quicker to the request, but is often more expensive.
XMP and EXPO
At default, the motherboard will set the memory clock to JEDEC (Joint Electron Device Engineering Council) standard speed to ensure the stability of the system. Most RAM today has pre-configured profiles with higher frequency and better timings along with the adjusted voltage. These profiles were tested and set to operate at specific platforms without issues – Extreme Memory Profile (XMP) for Intel and Extended Profiles for Overclocking (EXPO) for AMD. You can enable these profiles on your motherboard.
Look for the RAM profiles that is compatible with your system (some RAM has both XMP and EXPO profiles).
CUDIMM
As RAM speed gets faster, signal integrity becomes more susceptible to noise and interference making the system unstable and prone to crashes. To solve this problem, manufacturers added a small chip that regenerates the signal directly on the module and called this the clock driver (CKD). This allows the manufacturer to reach higher frequencies and add more capacity per module, like 9600 MT/s (4800 MHz) with 24 GB capacity. This new type of module is now called Clocked Unbuffered Dual In-Line Memory Module or CUDIMM.
Currently CUDIMM is only supported in Intel Core Ultra Series 2 processors (Arrow Lake) and Intel 890 chipset. Some motherboards with B860 and H810 chipsets may or may not support CUDIMM. Motherboards with AMD 800 series chipset currently supports CUDIMM but in bypass mode, but are expected to fully support soon. Bypass mode will run the CUDIMM but without the use of the clock driver chip and will run like regular DDR5 modules. The speed will also be dependent on the processor’s Integrated Memory Controller (IMC), potentially running the module at lower speed. It is also not recommended to mix CUDIMM and regular UDIMM.
1 Stick vs 2 Sticks vs 4 Sticks
Buying a single stick of RAM is not always a terrible idea because you can still add another RAM later on. A single stick of RAM with adequate capacity of 8 GB can still do light tasks like office work, browsing, and video playback. Nevertheless, we recommend this only if you are on a very tight budget. Otherwise, we recommend buying two memory modules right away. When properly installed, two sticks of RAM will activate dual-channel mode. This technology is like adding lanes on the road so more cars can travel.
The reason to consider buying four sticks of RAM is when you need lots of it for, e.g., rendering large 3D models or very complex video editing. Going with four sticks is usually the most cost-effective way to add considerable memory capacities for these types of tasks. The drawback is that likely you won’t be able to run the modules at its XMP or EXPO speeds. This is because you add modules for the CPU IMC (Integrated Memory Controller) to work on and it becomes less stable at higher speeds.
Also, you will still be running in dual-channel mode on the vast majority of gaming systems. Quad-channel technology is only available on high-end desktop (HEDT) workstations, and server platforms based on AMD Threadripper or Intel Xeon.
Heatsink and Cooler
RAM modules also produce heat and get hot as it is being filled and utilized. This happens when there are programs running at the same time or you are using a memory-intensive applications like 3D rendering, file compression, or games. RAM heatsinks and coolers help the memory chips to run cooler and have a longer life span compared to RAM modules without heatsinks. Bare RAM modules are fine for basic computing and if you are not overclocking. Fans are usually not necessary if you have a well-ventilated system.
RAM as an Upgrade
If you are buying RAM to upgrade a system with a single existing memory module, it is recommended to buy an identical module, i.e. same brand, model, capacity and clock. Having different modules can cause instability issues or even a refusal to boot. Although you can mix different RAM modules, your RAM speed will be limited by the slowest installed module. You will not be able to turn on XMP or EXPO.
QVL – Qualified Vendor List
Also look for the Qualified Vendor List (QVL) of your motherboard. In most cases, you will have no problems using any set of RAM sticks that conform to the specs and type listed by the motherboard manufacturer. However, RAM listed in the QVL has been tested and is guaranteed to work on your motherboard at the correct speed and timings.
QVLs are often compiled into “memory finder” tools by RAM or motherboard manufacturers, and offer an easier way to find compatible RAM for your system. Just key in your motherboard model to get a list of all compatible memory modules.
Pictured above is Corsair’s compatibility checker. Similar tools are available from Crucial and G-Skill, but these will only pair with RAM from these manufacturers, respectively.
Summary
Memory is one of the more affordable upgrades for your system. It will have major effects if your current configuration is inadequate, but too much RAM, on the other hand, is usually a waste. Below is a table we recommend for the amount of RAM for specific types of systems.
| 8 GB Single Channel | Office / school applications Light web browsing Watching movies |
| 8 GB (2x 4 GB) Dual Channel | Casual gaming, Old games Basic software / web development |
| 16 GB (2x 8 GB) Dual Channel | High-performance gaming, Competitive esports games Light photo / video / 3D modeling Software engineering, full-stack web development |
| 32 GB or more Dual / Quad Channel | High-performance gaming with livestreaming Full-length video editing Large scale 3D modeling |
Having 16 GB of RAM for office or home theatre PC is really a waste of money, while having a single stick of 8 GB RAM for new AAA titles and for competitive esport games will cause a bottleneck, meaning it will hinder faster components from operating at its maximum potential. If your budget allows, always go for 16 GB dual channel, quad-channel for workstations.
As for RAM speeds and timings, you may see significant FPS uplifts in some games (especially when CPU-bound at lower resolutions). But the fastest RAM is typically very expensive and often, your budget is better spent on a faster GPU.
