diff --git a/pep-0418.txt b/pep-0418.txt
index 008197d39..4ad113da8 100644
--- a/pep-0418.txt
+++ b/pep-0418.txt
@@ -509,9 +509,10 @@ days).
 The default precision of the timeGetTime function can be five
 milliseconds or more, depending on the machine.
 
-timeBeginPeriod() can be used to increase the precision of
-timeGetTime() up to 1 millisecond, but it negatively affects power
-consumption.
+timeBeginPeriod() can be used to increase the precision of timeGetTime() up to
+1 millisecond, but it negatively affects power consumption. Calling
+timeBeginPeriod() also affects the granularity of some other timing calls, such
+as CreateWaitableTimer(), WaitForSingleObject() and Sleep().
 
 .. note::