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64GB (2x32GB) NEMIX RAM Memory for 2019 Apple iMac 27 inch Retina 5K (iMac19,1 A2115), 2018 Apple Mac Mini (Macmini8,1 A1993) System Specific Memory - Newegg.com
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Timetec 32GB KIT(2x16GB) Compatible for Apple DDR4 2666MHz / 2667MHz for Mid 2020 iMac (20,1/20,2) / Mid 2019 iMac (19,1) 27-inch w/Retina 5K, Late 2018 Mac Mini (8,1) PC4-21333 /PC4-21300 MAC RAM at Amazon.com
128GB OWC 2666MHz DDR4 RDIMM PC4-21300 288-pin CL19 Quadruple Channel Memory Upgrade kit for iMac Pro (4x 32GB)
Amazon.com: OWC 32GB (2 x 16GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S32P) : Everything Else