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RAM upgrade guide: how much memory you need and how to add it

Updated October 30, 2026

If your PC slows to a crawl when you have lots of browser tabs or apps open, more memory (RAM) is often the cheapest fix that actually works. Here's how to tell whether you need it and how to buy the right kind.

Do you actually need more RAM?

Open the apps you normally use at the same time.
Press Ctrl + Shift + Esc to open Task Manager and click Performance › Memory.
If In use is regularly above about 85–90% of the total, or the Committed figure is higher than your installed memory, more RAM will help.

If memory use is low but the PC is slow, RAM isn't the problem — look at the drive (an HDD is the usual culprit), startup apps or free space instead.

How much is enough?

8 GB: the minimum for Windows 11 with light browsing and office work today; easily filled.
16 GB: the comfortable amount for most people, including most gaming.
32 GB: for heavy multitasking, newer demanding games with many apps open, photo and video editing.
64 GB or more: for large video projects, 3D, virtual machines or data work.

Find out what your PC takes

You need to match four things: type, form factor, free slots and a sensible speed.

Task Manager › Performance › Memory shows the speed, Slots used (for example “2 of 4”) and form factor (DIMM for desktops, SODIMM for laptops).
The memory type (DDR3, DDR4 or DDR5) is listed in your PC or motherboard manual; our free scan reads it for you.
DDR4 and DDR5 are physically different and can't be mixed or swapped.
Many thin laptops have memory soldered to the board and can't be upgraded. Check the manual or the manufacturer's support page before buying.

Choosing a kit

Buy matched pairs. Memory runs fastest in “dual channel”, so two identical sticks (a “kit”) beat one bigger stick.
Adding vs replacing: if you have two free slots, you can add a matching pair. Mixing different brands and speeds usually works but runs at the slowest stick's speed and sometimes causes instability; replacing everything with one new kit is the most reliable.
Desktops with DDR5: two sticks are usually more stable and faster than four.
Speed: buy the speed your platform supports well; faster kits are fine but will run at the motherboard's default speed until you enable XMP or EXPO in the BIOS.
Check the motherboard's “QVL” (qualified memory list) on the maker's website if you want to be extra safe.

Installing desktop RAM

Shut down, switch off the power supply and unplug the cable. Touch the metal case to discharge static.
Open the side panel. Find the memory slots next to the processor.
For two sticks in a four-slot board, the manual usually says to use slots A2 and B2 (often the second and fourth from the CPU).
Open the clips, line up the notch in the stick with the key in the slot, and press firmly straight down until the clips click.
Close the case, power on. The first start after a memory change can take a minute while the PC “trains” the memory — be patient.
In the BIOS, turn on XMP or EXPO to run the kit at its rated speed (optional).

Installing laptop RAM

Shut down, unplug the charger. Follow the manufacturer's service guide to remove the bottom cover. Some laptops require you to disconnect the internal battery first.
Release the clips at each side of the existing stick; it pops up at an angle.
Insert the new stick at about 30°, then press it flat until the clips lock.

Check it worked

Open Settings › System › About and check Installed RAM, then Task Manager for slot use and speed. If the PC won't start, reseat the sticks and try one at a time. To test for errors, search Start for Windows Memory Diagnostic.