Cheapest DDR3 RAM ranked by price per GB

DDR3 RAM: keeping an older PC or laptop useful

DDR3 was the standard from about 2008 to 2015, covering Intel Core 2 through 4th and 5th generation Core, AMD AM3 and FM2, and every laptop and Mac of that era. Nobody makes new DDR3 platforms, but millions of those machines are still in use, and adding memory is the cheapest way to make one usable again. The 1,133 DDR3 kits above are ranked by price per gigabyte, from £0.00/GB (median £5.84/GB), with the cheapest kit right now being ESUS IT MEMORY RAM UPGRADE 8GB for Apple Mac Mini MacBook Pro iMac DDR… at £0.01.

DDR3 versus DDR3L

The one detail that catches people out: DDR3L runs at 1.35V and standard DDR3 at 1.5V. Laptops and small desktops from roughly 2013 onward (Intel 4th gen Haswell and later) often require DDR3L and will not boot with 1.5V modules. DDR3L is backwards compatible and runs happily at 1.5V in an older machine, so when in doubt buy the DDR3L version; it appears in the same table and rarely costs more.

• Desktop DIMM (240 pins): 1333MHz was the mainstream, 1600MHz the enthusiast standard and the sensible buy now; 1866 and 2133 kits exist for AMD APUs and overclockers.
• Laptop SO-DIMM (204 pins): 1333 or 1600MHz. Also the upgrade for 2009 to 2015 iMacs, the 2012 to 2014 Mac mini and pre-2013 MacBook Pros, listed on the Mac page.
• Server ECC and registered DDR3: still common in used Xeon E5 v1 and v2 machines and very cheap per gigabyte on the server page.

How much DDR3 to add

A DDR3-era machine with 4GB is where Windows 10 or 11 struggles; taking it to 8GB is the single biggest improvement and often costs less than a takeaway. 16GB is the practical ceiling for most consumer DDR3 boards (four slots of 4GB, or two of 8GB) and plenty for browsing, office work and older games. 32GB was possible only on later boards with 8GB modules in all four slots. Check the maximum in the manual, and note that 32-bit Windows installs cannot use more than about 3.5GB whatever you fit.

Speeds on this page span 1,066 to 3,927MHz. Mixing speeds is fine on DDR3; the board runs everything at the slowest module's speed. Because most DDR3 sold now is second-hand or old stock, the price history on each product page is worth a glance: some listings drift up as new stock disappears, and Amazon Warehouse returns are frequently the best value. Corsair Vengeance and Kingston HyperX and ValueRAM are the ranges you will see most, alongside Crucial modules.