https://qooah.com/2016/02/17/%e5%b0%8f%e7%b1%b35-%e6%9c%80%e7%b5%82%e8%a6%8f%e6%a0%bc%e6%8f%ad%e6%9b%89-5-15%e5%90%8b%e5%b1%8f%e5%b9%95%e3%80%813gb-ram/