Installed replacement @corsair 8GB RAM into 2009 Apple MacBookPro5,5 mid-2009 A1278 MB990LL/A. Bought CMSA8GX3M2A1066C7 8GB SODIMM in Toronto in July, installed to upgrade from 2GB RAM but didn’t test fully until trying MacOS upgrade in September. Had crashes in OS X Mavericks 10.9.3, original OS X 10.5.7 Leopard DVD, OS X 10.11.5 El Capitan, yet MemTest86 said RAM was fine.
Corsair guarantees SODIMM to work with Mac, so requested RMA online on Sept. 21, got immediate authorization. Mailed RAM to California next day, got notification on Sept. 30 that memory had shipped. Hadn’t anticipated global supply chain, as package tracked on UPS from Taiwan to Anchorage to Louisville KY to Toronto.
Installed replacement SODIMM in MacBook Pro, system now seems stable. Activity Monitor shows MacOS Sierra with Chrome running in 2.6 of 8.0 GB of RAM, so performance of the computer should be better with the upgrade.