diff --git a/README.md b/README.md
index 722acce..4015547 100644
--- a/README.md
+++ b/README.md
@@ -415,9 +415,13 @@ If you encounter this, try these things
      slow down the GPIO writing a bit. This will of course reduce the
      frame-rate, so it comes at a cost.
 
-For GPIO slow-down, uncomment the following line in [lib/Makefile](lib/Makefile)
+For GPIO slow-down, the following line in the [lib/Makefile](lib/Makefile)
+is interesting:
 
-     #DEFINES+=-DRGB_SLOWDOWN_GPIO   # remove '#' in the beginning
+     DEFINES+=-DRGB_SLOWDOWN_GPIO=1
+
+The default value is 1, if you still have problems, try the value 2. If you
+know that your display is fast enough, try to comment out that line.
 
 Then `make` again.
 
diff --git a/lib/Makefile b/lib/Makefile
index f11b532..dacf2b0 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -32,7 +32,7 @@ TARGET=librgbmatrix.a
 # the frame-rate.
 # Sometimes, you even have to give RGB_SLOWDOWN_GPIO=2 for particularly slow
 # panels or bad signal cable situations.
-#DEFINES+=-DRGB_SLOWDOWN_GPIO=1
+DEFINES+=-DRGB_SLOWDOWN_GPIO=1
 
 # ------------ Pinout options; usually no change needed here --------------