https://blog.wongcw.com/2019/01/30/%e5%a4%a9%e6%a9%9f10%ef%bc%9f%e4%b8%ad%e8%88%88%e9%a9%8d%e9%be%8d855%e6%96%b0%e6%a9%9f%e7%8f%be%e8%ba%ab%e8%b7%91%e5%88%86%ef%bc%9a6gb-ram/