diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -97,7 +97,7 @@
         numfreeblocks--;
         return freeblocks[numfreeblocks];
     }
-    b = PyMem_Malloc(sizeof(block));
+    b = _PyMem_Malloc_Aligned(sizeof(block), 8*sizeof(PyObject *));
     if (b != NULL) {
         return b;
     }
diff --git a/Objects/setobject.c b/Objects/setobject.c
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -354,7 +354,7 @@
         }
     }
     else {
-        newtable = PyMem_NEW(setentry, newsize);
+        newtable = _PyMem_NEW_ALIGNED(setentry, newsize, 8*sizeof(setentry *));
         if (newtable == NULL) {
             PyErr_NoMemory();
             return -1;