Cheapest 8GB DDR3 RAM ranked by price per GB

8GB DDR3 RAM: topping up a 2010 to 2015 PC or laptop

An 8GB DDR3 kit is almost always an upgrade for a machine that already exists: a Core i3, i5 or i7 desktop from the Sandy Bridge to Haswell years, an AMD AM3 or FM2 build, a laptop bought before about 2016, or an older iMac or Mac mini. Nobody is building new DDR3 systems, but a 4GB machine of that era taken to 8GB goes from swapping constantly under Windows 10 to being perfectly usable for browsing, email and office work. The 322 8GB DDR3 kits and single sticks above are ranked by price per gigabyte, from £0.00/GB (median £3.46/GB); the cheapest right now is ESUS IT MEMORY RAM UPGRADE 8GB for Apple Mac Mini MacBook Pro iMac DDR… at £0.01.

DDR3 or DDR3L: check the voltage first

Standard DDR3 runs at 1.5V; DDR3L runs at 1.35V. Many laptops and small desktops from roughly 2013 onward (Intel 4th gen Haswell and later) require DDR3L and may refuse to boot with a 1.5V module. DDR3L is backwards compatible and runs at 1.5V in older machines, so if you are unsure, buy the DDR3L version; the DDR3L page lists those modules on their own. The voltage is printed on the label of the module already fitted, usually as "PC3L" for low voltage and "PC3" for standard.

Kit shapes at 8GB

• 1x8GB: the common choice for a laptop with one free slot, or for adding to a 4GB stick already fitted to reach 12GB. Some older boards, notably Intel Core 2 era chipsets, only accept up to 4GB per module, so check the manual before buying a single 8GB stick for a pre-2011 machine.
• 2x4GB: a matched pair that runs in dual channel, the right buy when you are replacing two 2GB sticks in a desktop or a two-slot laptop.

Form factor matters as much as generation. Desktops take the 240-pin DIMM; laptops, many all-in-ones, the 2012 to 2014 Mac mini and the 2009 to 2015 iMacs take the 204-pin SO-DIMM. The Form Factor column in the table is the reliable check; a listing title that says "laptop" on a full-size DIMM does happen.

Speed and latency on DDR3

Speeds on this page run from 1,066 to 3,927MHz. 1600MHz (PC3-12800) is the sensible buy now; 1333MHz (PC3-10600) was the earlier mainstream and is what many office PCs and laptops shipped with. A 1600MHz module in a 1333MHz machine simply runs at 1333, and mixing speeds is fine on DDR3, because everything drops to the slowest module. Latency is typically CL9 at 1333 and CL9 to CL11 at 1600; in a machine this age the difference is not something you will notice, so the £/GB ranking is the whole decision. The DDR3-1600 page narrows the list to that speed across all capacities.

Reading the table

Most DDR3 sold in 2026 is old stock or second-hand, so the same Kingston or Crucial part can appear from several sellers at quite different prices. Amazon Warehouse returns are frequently the cheapest per gigabyte, and memory either passes a test or it does not, so a used module is a low-risk buy; our Warehouse RAM guide covers what to check. The ECC and Buffered columns mark server modules from old Xeon machines; those will not work in a consumer board. If 8GB is not enough, the 16GB page includes DDR3 kits, which is the practical ceiling for most boards of this generation. For machines from 2016 onward, compare the 8GB DDR4 and 16GB DDR4 pages, or see all 8GB memory and the full DDR3 list.