How to Upgrade Your RAM: Step by Step Guide

Is your machine upgradeable?

Start with the question that rules everything else out. A RAM upgrade needs free or replaceable memory slots, and not every computer has them. Most tower desktops do. Many laptops do too, but some do not. If your computer is a notebook, our laptop RAM prices cover every SO-DIMM kit we track in UK shops.

The machines you cannot upgrade are easy to spot once you know where to look. Thin laptops often use LPDDR memory soldered straight onto the board. On Apple silicon Macs, Apple puts the memory inside the M-series chip package and says it cannot be upgraded, so the amount you ordered is the amount you keep. Some newer notebooks use CAMM2, a removable module that JEDEC published as a standard in December 2023 to replace soldered LPDDR. If the spec sheet for your model lists the memory as "onboard" or "soldered", stop here.

To find out what you have, note the exact model of the laptop or motherboard and open the maker's spec page or manual. In Windows, Task Manager shows how much memory is installed under Performance, then Memory. Kingston's online Configurator also lists the maximum memory a given system can use.

What to check before you order

Corsair publishes a checklist for upgrades, and it covers the questions that trip most people up. Before you put anything in a basket, write down:

• your motherboard model and processor;
• the most memory the board and processor support together;
• the memory generation the board takes;
• how many slots are free;
• how much height there is under a large air cooler, since tall heat spreaders can foul it;
• the type, number, size, speed, latency and brand of the sticks already fitted.

The generation is the check that matters most. You cannot swap DDR4 and DDR5: the notch on each module is cut in a different place, so neither one fits the other's slot. It is the motherboard that decides, not the processor alone. On Intel, 12th to 14th gen Core processors support either type and the board makes the choice. AMD AM5 and Intel Core Ultra 200S are DDR5 only.

AMD's older AM4 platform needs a separate note. AMD lists Ryzen 5000 chips such as the Ryzen 5 5600X with DDR4 only, up to 3200 MT/s. An AM4 owner can add DDR4, but switching to DDR5 means a new board and processor too. Our DDR5 vs DDR4 comparison explains when that jump is worth it. Older PCs that only take DDR3 can only be upgraded with a bigger DDR3 kit, according to Lexar.

Then check the module size. Desktops take full size DIMMs, while laptops and small form factor PCs take the shorter SO-DIMM. They are not interchangeable, which is why we list their prices separately.

Choosing the right kit

Buy one matched kit for the slots you plan to fill rather than adding a lone stick to what you already have. Mainstream desktops run their memory in dual channel, which means a pair of modules delivers the full bandwidth: a 2 x 16GB kit is quicker than one 32GB stick. Corsair says swapping every module for a kit sold together is the only way to guarantee they cooperate. Adding a second kit costs less, but it can fail, especially at speeds above what the CPU maker certifies.

Filling all four slots on a desktop board is possible, but it makes high speeds harder to hold. AMD's own figures for the Ryzen 7 9800X3D show the size of the drop: it is rated for DDR5-5600 when two modules are fitted, but only DDR5-3600 when all four are. If you want 64GB, two 32GB modules beat four 16GB ones.

On size, Newegg's 2026 guide is a sensible yardstick. 16GB covers browsing, office work, study and most 1080p gaming. 32GB suits gaming with a browser and chat running, photo editing and light video work. 64GB is for heavy video editing, 3D rendering, large datasets and local AI models. Our guide on how much RAM you need goes through each case.

The table shows the cheapest kit we found in UK shops this week for the most common upgrades.

All prices are including VAT and were checked on 2 November 2026. Desktop builders can compare every kit on the 32GB RAM prices page. Laptop owners can go straight to DDR5 laptop RAM or DDR4 laptop RAM.

Fitting RAM in a desktop PC

Power down completely and switch off at the back of the power supply before you open the case. Kingston warns that static discharge can damage components, so ground yourself on a bare metal object that is not part of the PC before you pick up the modules. An anti-static wrist strap is the better option if you have one.

These steps follow Corsair's own install guide:

1. Lay the case flat with the motherboard facing up so the slots are easy to reach.
2. To replace existing memory, push open the clips at each end of the slot and lift the old modules out.
3. Look up the slot order in the motherboard manual. Which two slots to use for a pair differs from board to board, so trust the manual over any rule of thumb.
4. Unlatch the clips on the slots you will fill.
5. Match the notch on the module to the ridge in the slot. DDR3, DDR4 and DDR5 each have the notch in a different spot, so a module of the wrong generation will not seat.
6. Press down evenly on both ends until you hear a click and the clips close by themselves.
7. Fit the second module the same way, then close the case and reconnect the power.

Fitting RAM in a laptop

The method is similar, but the slot sits differently. With the laptop off and the charger out, remove the base panel or the memory cover as the service manual describes.

Laptop SO-DIMM slots usually lie flat rather than standing upright as they do on a desktop board. Corsair's steps: where there are two slots, fill the lower one first. Align the notch, push the module in at an angle until the contacts are fully in, then press it down until the metal clips on each side lock it. To take a module out, spread the clips and it will lift up so you can pull it free.

If one module is already fitted and a slot is free, buy a stick that matches its type, size and speed. Stay within the maximum the laptop supports: Corsair notes that going over it can stop the laptop from booting.

Checking the upgrade worked

Switch on and let Windows load. Open Task Manager and confirm that the installed memory matches what you fitted. If the total is short, power down and reseat the module that is missing.

Then check the speed. A DDR5-6000 kit usually starts at a lower JEDEC default, typically 4800 or 5600 MT/s. To reach the speed printed on the box, go into the BIOS and switch on XMP (Intel) or EXPO (AMD AM5). Intel and AMD both describe these profiles as overclocking outside the official spec, and the rated speed assumes the profile is active.

If the computer will not start after you enable the profile, reset the BIOS to defaults and try a slower profile, or look up the board maker's list of tested memory. For what the speed and latency figures mean, see our RAM explainer.

Common mistakes

• Ordering the wrong generation. DDR4 and DDR5 sticks look almost identical in product photos. Confirm the board first.
• Buying desktop memory for a laptop. Laptops need SO-DIMMs, desktops need full size DIMMs.
• Topping up an old kit with one new stick. Modules that were not sold together may refuse to run at their rated speed.
• Using four sticks to reach 64GB. Four modules often run slower than two, so a 2 x 32GB kit is usually better.
• Leaving XMP or EXPO off. The kit then runs at its slow default speed.
• Forgetting the cooler. A tall heat spreader can clash with a big air cooler.
• Assuming every laptop has a slot. Check the spec sheet, because soldered memory cannot be changed.