diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 26402ea9cd..4b94940e99 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -36,7 +36,7 @@ from synapse.events.utils import prune_event
 
 from synapse.util.retryutils import NotRetryingDestination
 
-# from synapse.push.action_generator import ActionGenerator
+from synapse.push.action_generator import ActionGenerator
 
 from twisted.internet import defer
 
@@ -244,12 +244,11 @@ class FederationHandler(BaseHandler):
                     user = UserID.from_string(event.state_key)
                     yield user_joined_room(self.distributor, user, event.room_id)
 
-        # Temporarily disable notifications due to performance concerns.
-        # if not backfilled and not event.internal_metadata.is_outlier():
-        #     action_generator = ActionGenerator(self.store)
-        #     yield action_generator.handle_push_actions_for_event(
-        #         event, self
-        #     )
+        if not backfilled and not event.internal_metadata.is_outlier():
+            action_generator = ActionGenerator(self.store)
+            yield action_generator.handle_push_actions_for_event(
+                event, self
+            )
 
     @defer.inlineCallbacks
     def _filter_events_for_server(self, server_name, room_id, events):
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 1942268c3c..52202d8e63 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -841,9 +841,6 @@ class SyncHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def unread_notifs_for_room_id(self, room_id, sync_config, ephemeral_by_room):
-        # Temporarily disable notifications due to performance concerns.
-        defer.returnValue([])
-
         last_unread_event_id = self.last_read_event_id_for_room_and_user(
             room_id, sync_config.user.to_string(), ephemeral_by_room
         )
diff --git a/synapse/push/action_generator.py b/synapse/push/action_generator.py
index 73467f3adc..4cf94f6c61 100644
--- a/synapse/push/action_generator.py
+++ b/synapse/push/action_generator.py
@@ -36,9 +36,6 @@ class ActionGenerator:
 
     @defer.inlineCallbacks
     def handle_push_actions_for_event(self, event, handler):
-        # Temporarily disable notifications due to performance concerns.
-        return
-
         if event.type == EventTypes.Redaction and event.redacts is not None:
             yield self.store.remove_push_actions_for_event_id(
                 event.room_id, event.redacts