diff --git a/django/core/cache/__init__.py b/django/core/cache/__init__.py
index b17ad8185a..bb10e01c65 100644
--- a/django/core/cache/__init__.py
+++ b/django/core/cache/__init__.py
@@ -80,7 +80,7 @@ if not settings.CACHES:
         import warnings
         warnings.warn(
             "settings.CACHE_* is deprecated; use settings.CACHES instead.",
-            PendingDeprecationWarning
+            DeprecationWarning
         )
     else:
         # The default cache setting is put here so that we
diff --git a/django/core/cache/backends/memcached.py b/django/core/cache/backends/memcached.py
index c456f7f3c3..6cca2f8c7c 100644
--- a/django/core/cache/backends/memcached.py
+++ b/django/core/cache/backends/memcached.py
@@ -126,24 +126,18 @@ class BaseMemcachedCache(BaseCache):
     def clear(self):
         self._cache.flush_all()
 
-# For backwards compatibility -- the default cache class tries a
-# cascading lookup of cmemcache, then memcache.
 class CacheClass(BaseMemcachedCache):
     def __init__(self, server, params):
+        warnings.warn(
+            "memcached.CacheClass has been split into memcached.MemcachedCache and memcached.PyLibMCCache. Please update your cache backend setting.",
+            PendingDeprecationWarning
+        )
         try:
-            import cmemcache as memcache
-            import warnings
-            warnings.warn(
-                "Support for the 'cmemcache' library has been deprecated. Please use python-memcached or pyblimc instead.",
-                DeprecationWarning
-            )
-        except ImportError:
-            try:
-                import memcache
-            except:
-                raise InvalidCacheBackendError(
-                    "Memcached cache backend requires either the 'memcache' or 'cmemcache' library"
-                    )
+            import memcache
+        except:
+            raise InvalidCacheBackendError(
+                "Memcached cache backend requires either the 'memcache' or 'cmemcache' library"
+                )
         super(CacheClass, self).__init__(server, params,
                                          library=memcache,
                                          value_not_found_exception=ValueError)
diff --git a/docs/internals/deprecation.txt b/docs/internals/deprecation.txt
index 730f21d699..32f4b2d0b1 100644
--- a/docs/internals/deprecation.txt
+++ b/docs/internals/deprecation.txt
@@ -186,6 +186,12 @@ their deprecation, as per the :ref:`Django deprecation policy
           synonym for ``django.views.decorators.csrf.csrf_exempt``, which should
           be used to replace it.
 
+        * The :class:`~django.core.cache.backends.memcached.CacheClass` backend
+          was split into two in Django 1.3 in order to introduce support for
+          PyLibMC. The historical :class:`~django.core.cache.backends.memcached.CacheClass`
+          is now an alias for :class:`~django.core.cache.backends.memcached.MemcachedCache`.
+          In Django 1.6, the historical alias will be removed.
+
     * 2.0
         * ``django.views.defaults.shortcut()``. This function has been moved
           to ``django.contrib.contenttypes.views.shortcut()`` as part of the