Will DDR4 SO-DIMM fit your laptop?
Only if the laptop uses DDR4 and has a free or swappable SO-DIMM slot. The spec sheet or service manual for your exact model lists both, along with the largest capacity it supports. If the memory is soldered to the board, no module in the table will help. Our laptop RAM page covers every laptop memory type in one place.
SO-DIMM is the short module made for laptops and mini PCs, so a desktop stick from the DDR4 RAM prices page will not fit, even though it says DDR4 on the label. DDR5 SO-DIMM is no option either: Kingston notes that the notch sits in a different place, so the two types do not fit each other's slots.
In Windows, Task Manager under Performance, Memory shows the speed and how many slots are in use. If only one slot is filled, a second module of the same size and speed gives you dual channel.
Which size and speed should you buy?
Newegg's 2026 guidance puts 16GB as enough for browsing, office work and school, and 32GB as the safe choice for photo editing, light video work or the odd virtual machine. Our 16GB RAM prices and how much RAM you need pages go into the sizes in more detail. Kingston lists its FURY Impact DDR4 SO-DIMM line from 8GB up to 64GB, but only your spec sheet says whether the laptop can address that much.
On speed, the official DDR4 speeds stop at 3200 MT/s, often written as 3200MHz. Buy the speed your laptop's spec sheet names and do not pay extra for more. If it lists 2666 MT/s, modules at that speed start at £39.95 this week. The gap between the cheapest offer at each shop is 60%, so it pays to compare shops before you order.
What does the end of DDR4 mean for buyers?
Samsung, SK hynix and Micron announced in 2025 that they would wind down DDR4 and move capacity to DDR5, LPDDR5 and HBM. TrendForce says Taiwanese makers such as Nanya and Winbond are filling part of the gap, but not all of it. On the spot market, the benchmark DDR4 1Gx8 3200MT/s chip averaged US$46.357 on 20 October 2026, according to TrendForce, which described branded DDR4 trading as subdued.
Micron has also closed its Crucial consumer business, though it says Crucial products still on sale keep their warranty. If you want to keep an older laptop going, buy the size it needs now rather than waiting for a price drop nobody can promise. Change in the median price per GB over 4 weeks: not measured yet.