diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index 24770882d2..9341793a61 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -20,6 +20,7 @@ from twisted.internet import defer, reactor
 from synapse.events import FrozenEvent, USE_FROZEN_DICTS
 from synapse.events.utils import prune_event
 
+from synapse.util import unwrapFirstError
 from synapse.util.logcontext import preserve_context_over_deferred
 from synapse.util.logutils import log_function
 from synapse.api.constants import EventTypes
@@ -75,14 +76,31 @@ class EventsStore(SQLBaseStore):
                 for x in xrange(0, len(events_and_contexts), 100)
             ]
 
-            for chunk in chunks:
-                yield self.runInteraction(
-                    "persist_events",
-                    self._persist_events_txn,
-                    events_and_contexts=chunk,
-                    backfilled=backfilled,
-                    is_new_state=is_new_state,
-                )
+            if is_new_state:
+                # If is_new_state then we have to do chunks in order
+                for chunk in chunks:
+                    yield self.runInteraction(
+                        "persist_events",
+                        self._persist_events_txn,
+                        events_and_contexts=chunk,
+                        backfilled=backfilled,
+                        is_new_state=is_new_state,
+                    )
+            else:
+                # Otherwise, do them sequentially
+                yield defer.gatherResults(
+                    [
+                        self.runInteraction(
+                            "persist_events",
+                            self._persist_events_txn,
+                            events_and_contexts=chunk,
+                            backfilled=backfilled,
+                            is_new_state=is_new_state,
+                        )
+                        for chunk in chunks
+                    ],
+                    consumeErrors=True,
+                ).addErrback(unwrapFirstError)
 
     @defer.inlineCallbacks
     @log_function