Cheapest Mac-compatible RAM ranked by price per GB

Which Macs can still take RAM?

This page collects the 266 kits sold as Mac-compatible memory, ranked by price per gigabyte from £0.00/GB (median £6.23/GB). The cheapest kit right now is ESUS IT MEMORY RAM UPGRADE 8GB for Apple Mac Mini MacBook Pro iMac DDR… at £0.01. Before buying anything, confirm your model is on the short list of Macs with user-replaceable memory; every Apple Silicon Mac (M1 onward) has memory soldered to the chip package and cannot be upgraded, so the only fix there is buying more at purchase or choosing a different machine.

• 27-inch iMac, 2017 to 2020 (Retina 5K): four SO-DIMM slots behind a hatch on the back, DDR4 at 2400MHz (2017), 2666MHz (2019) or 2666/2933MHz (2020). Up to 128GB on the 2019 and 2020 models. The single easiest Mac upgrade there is.
• Mac mini 2018: two DDR4-2666 SO-DIMM slots, up to 64GB, but it needs the bottom cover and the logic board out, so it is a workbench job.
• Mac Pro 2019: twelve DIMM slots for DDR4-2933 ECC registered memory (RDIMM, or LRDIMM for 1.5TB); these are server modules and appear on the server page too.
• Older Intel Macs: 21.5-inch iMac 2017 (soldered) is out, but many 2009 to 2015 iMacs, the 2012 to 2014 Mac mini and pre-2013 MacBook Pros take DDR3 SO-DIMMs, usually 1600MHz.

Is "Mac memory" different?

Mostly no. A DDR4-2666 SO-DIMM sold for a Windows laptop is electrically the same as one sold for a 2019 iMac; what the Mac-branded kits from Crucial, Corsair (their Mac Memory range), OWC and Kingston add is confirmation that the specific timings and SPD profile have been tested on Apple hardware. That matters more than it sounds, because iMacs are fussier than PCs about mismatched modules and will slow the whole bank to the speed of the slowest stick. Buy a matched kit for the exact model, or buy an identical module to the one already fitted.

Because these listings overlap with ordinary laptop SO-DIMMs, it is worth checking that page too: the same Crucial or Kingston module often costs less without the word Mac in the title. Filter by generation (DDR4 for 2017 to 2020 iMacs and the 2018 mini, DDR3 for older machines) and by capacity; 32GB as a 2x16GB kit is the popular iMac upgrade, and 64GB as 2x32GB the ceiling for the Mac mini.

The For: Mac tag is detected from the listing text, so a few generic kits whose sellers mention iMac compatibility land here as well; that is fine, as long as the generation, form factor and speed match your model.