Cheapest SO-DIMM memory ranked by price per GB

SO-DIMM RAM: laptop, mini PC and small-form-factor memory

A SO-DIMM (small outline DIMM) is the short memory module used in laptops, mini PCs, NUCs, all-in-ones and plenty of other compact machines. It is roughly half the length of a desktop DIMM and carries the same memory chips. This page gathers every SO-DIMM generation in one table: 1,820 kits and modules ranked by price per gigabyte, from £0.00/GB to £81.61/GB with a median of £8.21/GB. The cheapest right now is ESUS IT MEMORY RAM UPGRADE 8GB for Apple Mac Mini MacBook Pro iMac DDR… at £0.01.

Pin counts: which generation is which

Each generation has its own pin count and notch position, so the wrong one will not go in the slot.

• 204 pins: DDR3 and DDR3L. Laptops and mini PCs from about 2008 to 2016. Machines from 2013 onward often need the 1.35V DDR3L type.
• 260 pins: DDR4. Laptops from roughly 2016 to 2023, most mini PCs and NUCs of that period, at 2400, 2666 or 3200MHz.
• 262 pins: DDR5. Laptops and mini PCs from 2022 onward, usually at 4800 or 5600MT/s.

Buying a faster SO-DIMM than the machine supports is harmless; it runs at the speed the system allows. Buying the wrong generation is not, so check the fitted module or the manual first. The generation pages for DDR4 and DDR5 list desktop and laptop modules together if you want to compare prices across form factors.

What is not a SO-DIMM

• Soldered LPDDR memory. Many thin laptops, every Apple Silicon Mac and most tablets use LPDDR4X or LPDDR5X chips soldered to the board. There is no slot and nothing to buy.
• LPCAMM2. A flat, screwed-down module carrying LPDDR5X, used in a few recent business and workstation laptops. It is replaceable, but it is a different part and not interchangeable with SO-DIMMs.
• CSODIMM. A DDR5 SO-DIMM variant with an on-module clock driver for higher speeds. It needs a platform built to support it, so do not assume one will work in place of an ordinary DDR5 SO-DIMM, or the other way round.

Where else SO-DIMMs turn up

Mini PCs and NUC-style machines almost all use SO-DIMMs, usually with two slots, and they are some of the easiest upgrades there are: one or two screws and the base comes off. SO-DIMMs are also used in some mini-ITX and thin-ITX motherboards, in compact x86 firewall and router boxes, in many small NAS units, and in all-in-one PCs. Older Intel iMacs and Mac minis take them too, and those are on the Mac page. Some NAS makers only support their own branded modules; a standard SO-DIMM of the right type usually works, but check the vendor's compatibility list before relying on one.

Choosing capacity

For a laptop or mini PC in 2026, 16GB is the sensible target and 32GB suits developers and heavy multitaskers. Two matched modules give dual channel, which makes a noticeable difference to integrated graphics. If one slot already holds a module, adding a second of the same generation, capacity and speed is the cheapest way to get there. The size pages 8GB laptop RAM, 16GB laptop RAM and 32GB laptop RAM narrow the table to one capacity, and the laptop page covers laptop-specific advice. Our laptop RAM upgrade guide explains how to check whether your machine can be upgraded at all.