diff --git a/retroshare-gui/src/gui/gxschannels/GxsChannelPostsModel.cpp b/retroshare-gui/src/gui/gxschannels/GxsChannelPostsModel.cpp
index 45b465955..c5a4b51cc 100644
--- a/retroshare-gui/src/gui/gxschannels/GxsChannelPostsModel.cpp
+++ b/retroshare-gui/src/gui/gxschannels/GxsChannelPostsModel.cpp
@@ -526,7 +526,7 @@ void RsGxsChannelPostsModel::updateSinglePost(const RsGxsChannelPost& post,std::
     triggerViewUpdate(true,false);
 }
 
-void RsGxsChannelPostsModel::setPosts(const RsGxsChannelGroup& group, std::vector<RsGxsChannelPost>& posts)
+void RsGxsChannelPostsModel::setPosts(const RsGxsChannelGroup& group, std::vector<RsGxsChannelPost>&& posts)
 {
 	preMods();
 
@@ -535,9 +535,17 @@ void RsGxsChannelPostsModel::setPosts(const RsGxsChannelGroup& group, std::vecto
 
 //    createPostsArray(posts);
 
-    mPosts = posts;
+    // The caller hands over its array and discards it right after, so take it
+    // rather than deep copying every post (and every thumbnail) one more time.
+    mPosts = std::move(posts);
+
+    // update_posts() already sorted the array in its loader thread. Kept as a
+    // cheap safety net for any other caller: on already ordered input this only
+    // costs comparisons, no element is moved.
 	std::sort(mPosts.begin(),mPosts.end());
 
+	mFilteredPosts.reserve(mPosts.size());
+
 	for(uint32_t i=0;i<mPosts.size();++i)
 		mFilteredPosts.push_back(i);
 
@@ -592,6 +600,13 @@ void RsGxsChannelPostsModel::update_posts(const RsGxsGroupId& group_id)
 			std::cerr << __PRETTY_FUNCTION__ << " failed to retrieve channel messages for channel " << group_id << std::endl;
 			return;
 		}
+
+        // Sort here rather than in setPosts(): setPosts() runs in the Qt thread,
+        // where sorting a few thousand posts is a visible freeze. The model only
+        // ever displays a sorted array, so the order may as well be established
+        // in this loader thread.
+        std::sort(posts->begin(),posts->end());
+
 #ifdef DEBUG_CHANNEL_MODEL
         std::cerr << "Got channel all content for channel " << group_id << std::endl;
         std::cerr << "  posts   : " << posts->size() << std::endl;
@@ -609,7 +624,7 @@ void RsGxsChannelPostsModel::update_posts(const RsGxsGroupId& group_id)
 			 * Qt::QueuedConnection is important!
 			 */
 
-            setPosts(group,*posts) ;
+            setPosts(group,std::move(*posts)) ;
 
             delete posts;
 
diff --git a/retroshare-gui/src/gui/gxschannels/GxsChannelPostsModel.h b/retroshare-gui/src/gui/gxschannels/GxsChannelPostsModel.h
index ad69e7594..a13712a41 100644
--- a/retroshare-gui/src/gui/gxschannels/GxsChannelPostsModel.h
+++ b/retroshare-gui/src/gui/gxschannels/GxsChannelPostsModel.h
@@ -239,7 +239,8 @@ private:
 	//void computeMessagesHierarchy(const RsGxsChannelGroup& forum_group, const std::vector<RsMsgMetaData> &msgs_array, std::vector<ChannelPostsModelPostEntry> &posts, std::map<RsGxsMessageId, std::vector<std::pair<time_t, RsGxsMessageId> > > &mPostVersions);
 	void old_createPostsArray(std::vector<RsGxsChannelPost> &posts);
     void createPostsArray(std::vector<RsGxsChannelPost>& posts);
-    void setPosts(const RsGxsChannelGroup& group, std::vector<RsGxsChannelPost> &posts);
+    /// Takes ownership of posts: the array is moved into the model.
+    void setPosts(const RsGxsChannelGroup& group, std::vector<RsGxsChannelPost> &&posts);
 public:
     void updateSinglePost(const RsGxsChannelPost& post, std::set<RsGxsFile>& added_files, std::set<RsGxsFile>& removed_files);
 private: