Cheapest DDR3L low-voltage RAM ranked by price per GB

DDR3L RAM: low-voltage memory for 2013 to 2016 laptops

DDR3L is the low-voltage version of DDR3. It runs at 1.35V instead of the 1.5V of standard DDR3, which saves a little power and heat and is why it became the norm in laptops, mini PCs and small desktops from about 2013 onward. The 160 DDR3L kits and modules above are ranked by price per gigabyte, from £1.78/GB with a median of £3.33/GB; the cheapest right now is Josenidny 8GB Memory RAM 2RX8 1.35V DDR3 PC3L-12800E 1600MHz 240 Pin E… at £14.21. Most of them are SO-DIMMs, because laptops are where DDR3L matters.

1.35V versus 1.5V: why it matters

The two types are physically identical: same notch, same 204 pins on a laptop SO-DIMM, same 240 pins on a desktop DIMM. The difference is the voltage the module is designed to run at, and that decides what will boot.

• DDR3L works in older 1.5V machines. Almost every DDR3L module is dual-voltage and runs at 1.5V when the board supplies it, so a DDR3L stick is a safe upgrade for a 2010 or 2011 laptop that originally took plain DDR3.
• Plain DDR3 does not reliably work in DDR3L-only laptops. Many laptops built on Intel 4th gen (Haswell), 5th gen (Broadwell) and the DDR3L versions of 6th gen (Skylake) supply only 1.35V to the memory. A 1.5V-only module in one of those may not boot at all, may beep, or may work until it warms up and then crash.

The practical rule is simple: if the laptop is from 2013 or later and takes DDR3, buy DDR3L. If it is older, DDR3L still works and costs about the same, so it is the safe default either way.

Reading the label: PC3L, 1600 and 1866

DDR3L modules are labelled PC3L followed by the bandwidth figure. PC3L-12800 is DDR3L-1600, the speed nearly every laptop of the era used, and the one to buy unless the manual says otherwise. PC3L-10600 is 1333MHz, found in some earlier and budget machines, and PC3L-14900 is 1866MHz, which a few later systems support. Memory always runs at the slowest speed the board and the modules agree on, so a 1600 stick in a 1333 laptop simply runs at 1333. A label ending in "S" (as in PC3L-12800S) marks a SO-DIMM; "U" marks an unbuffered desktop DIMM.

If you are matching a stick already fitted, look at its sticker or check Task Manager (Performance, then Memory) for the speed, and buy the same capacity and speed for a clean dual-channel pair. The full DDR3 range, including 1.5V modules for older desktops, is on the DDR3 page, and the 1600MHz desktop and laptop modules are also gathered on the DDR3-1600 page.

How much to add

Most laptops of this generation have two SO-DIMM slots and a maximum of 16GB, as two 8GB modules. Going from 4GB to 8GB is the upgrade that makes the biggest difference to Windows 10 on an older machine, and 8GB modules are the common size on this page (see the 8GB DDR3 page for the wider choice). A few business laptops and mini PCs from the period list 8GB per slot as the limit even if the chipset could address more, so check the manual before buying a 16GB kit. Pair the memory upgrade with an SSD if the laptop still has a hard disk; together they keep a 2014 machine usable for everyday work.

Most DDR3L for sale now is old stock or second-hand, so the price history on each product page is worth a glance before buying. Crucial and Kingston made the bulk of the retail DDR3L SO-DIMMs, and Samsung OEM modules pulled from laptops are common and cheap. Our laptop RAM upgrade guide covers finding the slots and fitting the module.