diff --git a/modules/client/sync.cc b/modules/client/sync.cc
index 5823b8db4..92af40496 100644
--- a/modules/client/sync.cc
+++ b/modules/client/sync.cc
@@ -24,6 +24,7 @@ namespace ircd::m::sync
 	extern conf::item<size_t> buffer_size;
 	extern conf::item<size_t> linear_buffer_size;
 	extern conf::item<size_t> linear_delta_max;
+	extern conf::item<size_t> polylog_prefetch;
 	extern conf::item<bool> longpoll_enable;
 	extern conf::item<bool> polylog_phased;
 	extern conf::item<bool> polylog_only;
@@ -133,6 +134,13 @@ ircd::m::sync::linear_delta_max
 	{ "help",     linear_delta_max_help                },
 };
 
+decltype(ircd::m::sync::polylog_prefetch)
+ircd::m::sync::polylog_prefetch
+{
+	{ "name",     "ircd.client.sync.polylog.prefetch"  },
+	{ "default",  8192                                 },
+};
+
 decltype(ircd::m::sync::polylog_phased)
 ircd::m::sync::polylog_phased
 {
@@ -1036,8 +1044,15 @@ try
 		*data.out
 	};
 
-	// Prefetch loop
-	if(data.range.first == 0)
+	const bool prefetch
+	{
+		false
+		|| (data.range.first == 0 && bool(polylog_prefetch))
+		|| (data.range.second - data.range.first > size_t(polylog_prefetch))
+	};
+
+	// Branch to run a prefetch loop.
+	if(prefetch)
 	{
 		const scope_restore prefetching
 		{
diff --git a/modules/client/sync/rooms.cc b/modules/client/sync/rooms.cc
index 3bc787d4d..b6f5a1541 100644
--- a/modules/client/sync/rooms.cc
+++ b/modules/client/sync/rooms.cc
@@ -141,6 +141,9 @@ ircd::m::sync::rooms_polylog(data &data)
 	bool ret{false};
 	int64_t phase(0);
 
+	if(data.prefetch)
+		data.user_rooms.prefetch();
+
 	ret |= _rooms_polylog(data, "join", phase);
 	if(data.phased && ret)
 		return ret;