diff --git a/lec5/p1-memintro.md b/lec5/p1-memintro.md
index f04f8a68..cf538ba8 100644
--- a/lec5/p1-memintro.md
+++ b/lec5/p1-memintro.md
@@ -62,7 +62,10 @@ backgroundColor: white
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 ##### 计算机的存储多层结构
-![w:950](figs/mem-layers.png)
+![w:700](figs/mem-layers.png)
+
+比较新的各种存储介质的访问速度参数：
+* [金字塔层次结构](https://www.cnblogs.com/binarylei/p/12588928.html)：越靠近CPU速度越快，容量越小，价格越贵
 
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