diff --git a/Performance-Tips.md b/Performance-Tips.md
index b3ac69b..0b3ff9a 100644
--- a/Performance-Tips.md
+++ b/Performance-Tips.md
@@ -12,7 +12,7 @@ One drawing function like `DrawImage` or `Fill` is treated as one (internal) dra
 
 examples/sprites is a good example to draw > 10000 sprites with one draw commands.
 
-# Avoid changing render sources too often
+# Avoid changing render sources' pixels
 
 Ebiten records almost all draw functions in order to restore when context lost happens. When a render source's pixel is changed after it is used as a render source, Ebiten tries a complicated calculation for restoring.