diff --git a/Misc/NEWS b/Misc/NEWS
index 1bbec39..1598c64 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@
 Core and builtins
 -----------------
 
+- The implementation of set() and frozenset() was revised to use its
+  own internal data structure.  Memory consumption is reduced by 1/3
+  and there are modest speed-ups as well.  The API is unchanged.
+
 - SF bug #1238681:  freed pointer is used in longobject.c:long_pow().
 
 - SF bug #1229429: PyObject_CallMethod failed to decrement some