If someone already has an 8 GB machine, Sequoia will surely run "ok" on it, as Apple is still stupidly selling lower-end machines with 8 GB as standard. An aspect where Apple's cheapness and in a sense meanness shows up the most clearly. Apple should have stopped selling 8 GB machines 10 years ago, maybe 20 years ago

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If someone is considering buying a new machine with 8 GB of RAM. Just NO. Do not do it, get 16 or 24 or 32 or more. Memory is still way way faster than even the latest SSD's, and you WILL notice it running a browser with a lot of tabs, or potentially some of the new machine learning/AI stuff which may wind up needing to use some of the system ram for processing.