diff --git a/public/src/forum/topic.js b/public/src/forum/topic.js
index 6c0ece91df..6acbcc7354 100644
--- a/public/src/forum/topic.js
+++ b/public/src/forum/topic.js
@@ -149,7 +149,7 @@ define('forum/topic', dependencies, function(pagination, infinitescroll, threadT
 			var postcount = $('.user_postcount_' + data.posts[i].uid);
 			postcount.html(parseInt(postcount.html(), 10) + 1);
 		}
-		socket.emit('topics.markAsRead', tid);
+		socket.emit('topics.markAsRead', [tid]);
 		createNewPosts(data);
 	}
 
diff --git a/public/src/forum/unread.js b/public/src/forum/unread.js
index f8e1a9be63..a3e3bb1b10 100644
--- a/public/src/forum/unread.js
+++ b/public/src/forum/unread.js
@@ -25,7 +25,7 @@ define('forum/unread', ['forum/recent', 'topicSelect', 'forum/infinitescroll'],
 			if(!tids.length) {
 				return;
 			}
-			socket.emit('topics.markTidsRead', tids, function(err) {
+			socket.emit('topics.markAsRead', tids, function(err) {
 				if(err) {
 					return app.alertError(err.message);
 				}
diff --git a/src/categories.js b/src/categories.js
index aaf732151b..315f6e8c4f 100644
--- a/src/categories.js
+++ b/src/categories.js
@@ -74,7 +74,7 @@ var db = require('./database'),
 			var category = categories[0];
 
 			if (parseInt(uid, 10)) {
-				Categories.markAsRead(cid, uid);
+				Categories.markAsRead([cid], uid);
 			}
 
 			async.parallel({
@@ -250,8 +250,14 @@ var db = require('./database'),
 		});
 	};
 
-	Categories.markAsRead = function(cid, uid, callback) {
-		db.setAdd('cid:' + cid + ':read_by_uid', uid, callback);
+	Categories.markAsRead = function(cids, uid, callback) {
+		if (!Array.isArray(cids) || !cids.length) {
+			return callback();
+		}
+		var keys = cids.map(function(cid) {
+			return 'cid:' + cid + ':read_by_uid';
+		});
+		db.setsAdd(keys, uid, callback);
 	};
 
 	Categories.markAsUnreadForAll = function(cid, callback) {
diff --git a/src/database/level/sets.js b/src/database/level/sets.js
index df10f4a632..525477db7d 100644
--- a/src/database/level/sets.js
+++ b/src/database/level/sets.js
@@ -19,6 +19,10 @@ module.exports = function(db, module) {
 		});
 	};
 
+	module.setsAdd = function(keys, value, callback) {
+		throw new Error('not-implemented');
+	};
+
 	module.setRemove = function(key, value, callback) {
 		module.getListRange(key, 0, -1, function(err, set) {
 			module.set(key, set.splice(set.indexOf(value), 1), callback);
diff --git a/src/database/mongo/sets.js b/src/database/mongo/sets.js
index 927337fbff..d247a1f945 100644
--- a/src/database/mongo/sets.js
+++ b/src/database/mongo/sets.js
@@ -31,6 +31,31 @@ module.exports = function(db, module) {
 		});
 	};
 
+	module.setsAdd = function(keys, value, callback) {
+		callback = callback || helpers.noop;
+		if(!Array.isArray(value)) {
+			value = [value];
+		}
+
+		value.forEach(function(element, index, array) {
+			array[index] = helpers.valueToString(element);
+		});
+
+		var bulk = db.collection('objects').initializeUnorderedBulkOp();
+
+		for(var i=0; i<keys.length; ++i) {
+			bulk.find({_key: keys[i]}).upsert().updateOne({	$addToSet: {
+				members: {
+					$each: value
+				}
+			}});
+		}
+
+		bulk.execute(function(err) {
+			return callback(err);
+		});
+	};
+
 	module.setRemove = function(key, value, callback) {
 		callback = callback || helpers.noop;
 		if(!Array.isArray(value)) {
diff --git a/src/database/redis/sets.js b/src/database/redis/sets.js
index 2ceb2cb252..e3a4790862 100644
--- a/src/database/redis/sets.js
+++ b/src/database/redis/sets.js
@@ -8,6 +8,17 @@ module.exports = function(redisClient, module) {
 		});
 	};
 
+	module.setsAdd = function(keys, value, callback) {
+		callback = callback || function() {};
+		var multi = redisClient.multi();
+		for (var i=0; i<keys.length; ++i) {
+			multi.sadd(keys[i], value);
+		}
+		multi.exec(function(err) {
+			callback(err);
+		});
+	};
+
 	module.setRemove = function(key, value, callback) {
 		redisClient.srem(key, value, callback);
 	};
diff --git a/src/socket.io/topics.js b/src/socket.io/topics.js
index 485344f885..47958809f1 100644
--- a/src/socket.io/topics.js
+++ b/src/socket.io/topics.js
@@ -61,8 +61,7 @@ SocketTopics.enter = function(socket, tid, callback) {
 	if (!tid || !socket.uid) {
 		return;
 	}
-	SocketTopics.markAsRead(socket, tid);
-	topics.markTopicNotificationsRead(tid, socket.uid);
+	SocketTopics.markAsRead(socket, [tid], callback);
 	topics.increaseViewCount(tid);
 	websockets.updateRoomBrowsingText('topic_' + tid);
 };
@@ -75,23 +74,17 @@ SocketTopics.increaseViewCount = function(socket, tid) {
 	topics.increaseViewCount(tid);
 };
 
-SocketTopics.markAsRead = function(socket, tid) {
-	if(!tid || !socket.uid) {
-		return;
+SocketTopics.markAsRead = function(socket, tids, callback) {
+	if(!Array.isArray(tids) || !socket.uid) {
+		return callback(new Error('[[error:invalid-data]]'));
 	}
 
-	topics.markAsRead(tid, socket.uid, function(err) {
-		topics.pushUnreadCount(socket.uid);
-	});
-};
-
-SocketTopics.markTidsRead = function(socket, tids, callback) {
-	if (!Array.isArray(tids)) {
-		return callback(new Error('[[error:invalid-data]]'));
+	if (!tids.length) {
+		return callback();
 	}
 
-	topics.markTidsRead(socket.uid, tids, function(err) {
-		if(err) {
+	topics.markAsRead(tids, socket.uid, function(err) {
+		if (err) {
 			return callback(err);
 		}
 
@@ -100,7 +93,6 @@ SocketTopics.markTidsRead = function(socket, tids, callback) {
 		for (var i=0; i<tids.length; ++i) {
 			topics.markTopicNotificationsRead(tids[i], socket.uid);
 		}
-
 		callback();
 	});
 };
@@ -118,7 +110,7 @@ SocketTopics.markAllRead = function(socket, data, callback) {
 			return callback(err);
 		}
 
-		SocketTopics.markTidsRead(socket, tids, callback);
+		SocketTopics.markAsRead(socket, tids, callback);
 	});
 };
 
@@ -138,14 +130,13 @@ SocketTopics.markCategoryTopicsRead = function(socket, cid, callback) {
 			}
 
 			tids = topicData.filter(function(topic) {
-				return parseInt(topic.cid, 10) === parseInt(cid, 10);
+				return topic && parseInt(topic.cid, 10) === parseInt(cid, 10);
 			}).map(function(topic) {
 				return topic.tid;
 			});
 
-			SocketTopics.markTidsRead(socket, tids, callback);
+			SocketTopics.markAsRead(socket, tids, callback);
 		});
-
 	});
 };
 
diff --git a/src/topics/create.js b/src/topics/create.js
index 7d35e9ba92..713fb7daf6 100644
--- a/src/topics/create.js
+++ b/src/topics/create.js
@@ -208,7 +208,7 @@ module.exports = function(Topics) {
 				Topics.markAsUnreadForAll(tid, next);
 			},
 			function(next) {
-				Topics.markAsRead(tid, uid, next);
+				Topics.markAsRead([tid], uid, next);
 			},
 			function(next) {
 				posts.getUserInfoForPosts([postData.uid], next);
diff --git a/src/topics/unread.js b/src/topics/unread.js
index 839034b010..1c44f8cc5f 100644
--- a/src/topics/unread.js
+++ b/src/topics/unread.js
@@ -162,7 +162,7 @@ module.exports = function(Topics) {
 		} else {
 		    return null;
 		}
-		
+
 		var	websockets = require('./../socket.io');
 
 		if (!uids) {
@@ -200,29 +200,35 @@ module.exports = function(Topics) {
 		});
 	};
 
-	Topics.markTidsRead = function(uid, tids, callback) {
-		if(!tids || !tids.length) {
+	Topics.markAsRead = function(tids, uid, callback) {
+		callback = callback || function() {};
+		if (!Array.isArray(tids) || !tids.length) {
 			return callback();
 		}
+		tids = tids.filter(Boolean);
+		var keys = tids.map(function(tid) {
+			return 'tid:' + tid + ':read_by_uid';
+		});
 
-		async.each(tids, function (tid, next) {
-			Topics.markAsRead(tid, uid, next);
-		}, callback);
-	};
-
-	Topics.markAsRead = function(tid, uid, callback) {
-		db.setAdd('tid:' + tid + ':read_by_uid', uid, function(err) {
+		async.parallel({
+			markRead: function(next) {
+				db.setsAdd(keys, uid, next);
+			},
+			topicData: function(next) {
+				Topics.getTopicsFields(tids, ['cid'], next);
+			}
+		}, function(err, results) {
 			if (err) {
 				return callback(err);
 			}
 
-			Topics.getTopicField(tid, 'cid', function(err, cid) {
-				if (err) {
-					return callback(err);
-				}
-
-				categories.markAsRead(cid, uid, callback);
+			var cids = results.topicData.map(function(topic) {
+				return topic && topic.cid;
+			}).filter(function(topic, index, array) {
+				return topic && array.indexOf(topic) === index;
 			});
+
+			categories.markAsRead(cids, uid, callback);
 		});
 	};