diff --git a/synapse/server.py b/synapse/server.py
index 9f06b83f94..d0e6f850a4 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -242,6 +242,7 @@ class HomeServer(object):
             self.datastores = DataStores(datastore, conn, self)
             conn.commit()
         self.start_time = int(self.get_clock().time())
+        self.get_clock().looping_call(self.config.caches.resize_caches, 10000)
         logger.info("Finished setting up.")
 
     def setup_master(self):
@@ -252,7 +253,6 @@ class HomeServer(object):
         """
         for i in self.REQUIRED_ON_MASTER_STARTUP:
             getattr(self, "get_" + i)()
-        self.config.caches.resize_caches()
 
     def get_reactor(self):
         """
diff --git a/synapse/storage/data_stores/main/state.py b/synapse/storage/data_stores/main/state.py
index 2c8f2c184f..180b75c710 100644
--- a/synapse/storage/data_stores/main/state.py
+++ b/synapse/storage/data_stores/main/state.py
@@ -246,14 +246,10 @@ class StateGroupWorkerStore(
         # We size the non-members cache to be smaller than the members cache as the
         # vast majority of state in Matrix (today) is member events.
 
-        self._state_group_cache = DictionaryCache(
-            "*stateGroupCache*",
-            # TODO: this hasn't been tuned yet
-            50000 * hs.config.caches.get_factor_for("stateGroupCache"),
-        )
+        # TODO: this hasn't been tuned yet
+        self._state_group_cache = DictionaryCache("*stateGroupCache*", 50000)
         self._state_group_members_cache = DictionaryCache(
-            "*stateGroupMembersCache*",
-            500000 * hs.config.caches.get_factor_for("stateGroupMembersCache"),
+            "*stateGroupMembersCache*", 500000
         )
 
     @defer.inlineCallbacks