What is RAM? Types, speeds and how much you need
RAM is the short term memory of your computer. Here is what it does, which type fits your PC and how much you need, with this week's US prices next to every option.
Key takeaways
- RAM holds the data your programs use right now; it is wiped when the computer turns off.
- Your motherboard decides the type: DDR4 and DDR5 modules do not fit each other's slots.
- 16GB is enough for office work and most games; 32GB is the comfortable size for gaming with other apps open and for editing.
- Two matching modules beat one large module on a desktop, because they run in dual channel.
What does RAM do?
RAM (random access memory) is the working memory of a computer. When you open a program, a browser tab or a game, the processor loads the data it needs from the SSD into RAM, because RAM is many times faster to read and write. The processor then works from RAM, not from the SSD.
RAM is volatile: everything in it disappears when the computer turns off. That is why your files live on the SSD and only the things you are using right now sit in RAM. When RAM fills up, the system starts moving data back to the much slower SSD. You notice that as stutter, slow tab switching and long waits after alt tab.
RAM versus storage
People often mix the two up because both are measured in gigabytes. A typical PC in 2026 has 16 or 32GB of RAM and 1 or 2TB of storage. More storage lets you keep more files and games installed. More RAM lets you keep more of them open at the same time without slowing down.
Buying more RAM does not free up disk space, and a bigger SSD does not fix a PC that runs out of memory. Check which of the two is full before you spend money: the Task Manager on Windows (tab Performance) shows memory use in real time.
DDR3, DDR4 and DDR5
Desktop and laptop memory comes in generations, and each generation only fits its own motherboards. DDR5 runs at 1.1 volt instead of 1.2 volt for DDR4 and has the notch in the module in a different place, so a DDR5 module does not go into a DDR4 slot. DDR5 also starts at 4800 MT/s, where the official DDR4 speeds end at 3200 MT/s.
You can read the generation on the label of a module or in the specifications of your motherboard. A label such as PC5-48000 means DDR5, PC4-25600 means DDR4.
The table below shows the three generations with the cheapest 16GB desktop kit we found in US shops this week.
| Type | Typical speed | Voltage | Cheapest 16GB desktop kit this week |
|---|---|---|---|
| DDR3 | 1333 to 1866 MT/s | 1.5 V | $36.54 |
| DDR4 | 2400 to 3600 MT/s | 1.2 V | $79.99 |
| DDR5 | 4800 to 8000 MT/s | 1.1 V | $228.99 |
DDR3 is only interesting if you keep an old PC running. DDR4 is still sold for the many systems from 2016 to 2022 that use it. The current AMD AM5 and Intel Core Ultra desktop platforms only take DDR5.
Speed and latency in plain words
Two numbers on the label tell you how fast a kit is. The speed in MT/s (often written as MHz) says how many transfers per second the memory does. The CAS latency (CL) says how many clock cycles the memory waits before it answers. Higher speed is better, lower CL is better, and the two balance each other: DDR5 6000 CL30 and DDR5 6400 CL32 respond in about the same time.
For AMD Ryzen 7000 processors, AMD itself called DDR5 6000 the sweet spot, and that kit size is still the common choice for new AM5 builds. Faster kits cost more and often need manual tuning. A new kit runs at a slow default speed until you enable its XMP (Intel) or EXPO (AMD) profile in the BIOS.
Look up your motherboard model and check its memory support list. It tells you the type (DDR4 or DDR5), the maximum capacity and the speeds that were tested.
How much RAM do you need?
Microsoft lists 4GB as the minimum for Windows 11, but that is a floor, not a recommendation. For daily use with a browser, mail and office apps, 16GB keeps things smooth. For gaming with Discord, a browser and a launcher open at the same time, 32GB is the comfortable size, and it gives you room for the next years. Video editing, large photo libraries, virtual machines and local AI models can use 64GB or more.
On a desktop, buy the capacity as a kit of two modules: 2x8GB for 16GB, 2x16GB for 32GB. Two modules run in dual channel, which gives the processor twice the memory bandwidth of a single module. Our 32GB price page lists every kit in that size with this week's price.
If you are not sure whether more memory will help, open the Task Manager while you do your normal work and look at the memory graph. If it stays above about 85% most of the time, more RAM will help. If it stays well below that, a faster SSD or processor will make a bigger difference than extra memory.
Desktop and laptop memory
Laptops use a shorter module called SO-DIMM. It works the same way, but it does not fit a desktop slot, and a desktop module does not fit a laptop. Many thin laptops have memory soldered to the board, which means you cannot upgrade it at all. Check the service manual or the spec sheet of your laptop before you order. Laptop modules also have their own prices, usually a little different from desktop kits of the same size: our laptop RAM page shows them side by side when it is live.
Common mistakes
- Buying the wrong generation. DDR4 and DDR5 look alike in a photo. Check the motherboard first.
- Mixing two different kits. Two kits that were not tested together can refuse to run at their rated speed, or at all.
- Forgetting XMP or EXPO. Without the profile, a fast kit runs at its slow default speed.
- Paying for speed you will not notice. Going from 6000 to 7200 MT/s costs more than it gives in most games. Capacity matters more once you run out.
- Upgrading a laptop with soldered memory. Some models have no free slot at all.
Questions
Is RAM the same as storage?
No. Storage (an SSD or hard drive) keeps your files when the computer is off. RAM only holds what is in use right now and is much faster, but it is emptied at every shutdown.
Can I mix DDR4 and DDR5?
No. The modules have the notch in a different place and run at different voltages. A motherboard supports one of the two types.
Does faster RAM make games faster?
A little, mostly on AMD Ryzen systems and in games that lean on the processor. Going from 16GB to 32GB matters more than going from 5600 to 6400 MT/s once 16GB is too small.
What does RAM cost right now?
This week the cheapest 16GB DDR5 desktop kit costs $228.99 and the cheapest 32GB DDR5 desktop kit $389.99 in our US data. Prices are excluding sales tax.
Sources
Gregory is the pen name for the theRAMageddon price guides and explainers. Drafts are written with AI assistance from our own weekly price data, following our editorial policy.