diff --git a/src/components/structures/RoomDirectory.js b/src/components/structures/RoomDirectory.js
index 8a2b52b9..d506e583 100644
--- a/src/components/structures/RoomDirectory.js
+++ b/src/components/structures/RoomDirectory.js
@@ -98,15 +98,16 @@ module.exports = React.createClass({
         if (!MatrixClientPeg.get()) return q();
 
         const my_filter_string = this.filterString;
+        const my_server = this.state.roomServer;
         const opts = {limit: 20};
-        if (this.state.roomServer != MatrixClientPeg.getHomeServerName()) {
-            opts.server = this.state.roomServer;
+        if (my_server != MatrixClientPeg.getHomeServerName()) {
+            opts.server = my_server;
         }
         if (this.nextBatch) opts.since = this.nextBatch;
         if (this.filterString) opts.filter = { generic_search_term: my_filter_string } ;
         return MatrixClientPeg.get().publicRooms(opts).then((data) => {
-            if (my_filter_string != this.filterString) {
-                // if the filter has changed since this request was sent,
+            if (my_filter_string != this.filterString || my_server != this.state.roomServer) {
+                // if the filter or server has changed since this request was sent,
                 // throw away the result (don't even clear the busy flag
                 // since we must still have a request in flight)
                 return;
@@ -120,7 +121,7 @@ module.exports = React.createClass({
             });
             return Boolean(data.next_batch);
         }, (err) => {
-            if (my_filter_string != this.filterString) {
+            if (my_filter_string != this.filterString || my_server != this.state.roomServer) {
                 // as above: we don't care about errors for old
                 // requests either
                 return;
@@ -195,10 +196,22 @@ module.exports = React.createClass({
     },
 
     onOptionChange: function(server, network) {
+        // clear next batch so we don't try to load more rooms
+        this.nextBatch = null;
         this.setState({
+            // Clear the public rooms out here otherwise we needlessly
+            // spend time filtering lots of rooms when we're about to
+            // to clear the list anyway.
+            publicRooms: [],
             roomServer: server,
             filterByNetwork: network,
         }, this.refreshRoomList);
+        // We also refresh the room list each time even though this
+        // filtering is client-side. It hopefully won't be client side
+        // for very long, and we may have fetched a thousand rooms to
+        // find the five gitter ones, at which point we do not want
+        // to render all those rooms when switching back to 'all networks'.
+        // Easiest to just blow away the state & re-fetch.
     },
 
     onFillRequest: function(backwards) {