https://blog.wongcw.com/2019/05/18/%e7%be%8e%e5%85%89ddr4%e5%85%a7%e5%ad%98%e6%89%93%e7%a0%b4%e8%b6%85%e9%a0%bb%e4%b8%96%e7%95%8c%e7%b4%80%e9%8c%84%e7%8b%82%e9%a3%865726mhz/