diff --git a/core/user.class.php b/core/user.class.php
index d9b9c45d..60c8fa48 100644
--- a/core/user.class.php
+++ b/core/user.class.php
@@ -67,7 +67,7 @@ class User {
 	 */
 	public static function by_session(/*string*/ $name, /*string*/ $session) {
 		global $config, $database;
-		$row = $database->cache->get("user-session-$name-$session");
+		$row = $database->cache->get("user-session:$name-$session");
 		if(!$row) {
 			if($database->get_driver_name() === "mysql") {
 				$query = "SELECT * FROM users WHERE name = :name AND md5(concat(pass, :ip)) = :sess";
@@ -76,7 +76,7 @@ class User {
 				$query = "SELECT * FROM users WHERE name = :name AND md5(pass || :ip) = :sess";
 			}
 			$row = $database->get_row($query, array("name"=>$name, "ip"=>get_session_ip($config), "sess"=>$session));
-			$database->cache->set("user-session-$name-$session", $row, 600);
+			$database->cache->set("user-session:$name-$session", $row, 600);
 		}
 		return is_null($row) ? null : new User($row);
 	}
diff --git a/ext/featured/main.php b/ext/featured/main.php
index e0a23676..0b643633 100644
--- a/ext/featured/main.php
+++ b/ext/featured/main.php
@@ -60,13 +60,13 @@ class Featured extends Extension {
 		global $config, $database, $page, $user;
 		$fid = $config->get_int("featured_id");
 		if($fid > 0) {
-			$image = $database->cache->get("featured_image_object-$fid");
+			$image = $database->cache->get("featured_image_object:$fid");
 			if($image === false) {
 				$image = Image::by_id($fid);
 				if($image) { // make sure the object is fully populated before saving
 					$image->get_tag_array();
 				}
-				$database->cache->set("featured_image_object-$fid", $image, 600);
+				$database->cache->set("featured_image_object:$fid", $image, 600);
 			}
 			if(!is_null($image)) {
 				if(class_exists("Ratings")) {
diff --git a/ext/index/main.php b/ext/index/main.php
index c3250bf7..99921d27 100644
--- a/ext/index/main.php
+++ b/ext/index/main.php
@@ -260,10 +260,10 @@ class Index extends Extension {
 				#log_debug("index", "Search for ".implode(" ", $search_terms), false, array("terms"=>$search_terms));
 				$total_pages = Image::count_pages($search_terms);
 				if(SPEED_HAX && $count_search_terms === 0 && ($page_number < 10)) { // extra caching for the first few post/list pages
-					$images = $database->cache->get("post-list-$page_number");
+					$images = $database->cache->get("post-list:$page_number");
 					if(!$images) {
 						$images = Image::find_images(($page_number-1)*$page_size, $page_size, $search_terms);
-						$database->cache->set("post-list-$page_number", $images, 600);
+						$database->cache->set("post-list:$page_number", $images, 600);
 					}
 				}
 				else {
diff --git a/ext/pm/main.php b/ext/pm/main.php
index 2deaf4e4..e07d44a4 100644
--- a/ext/pm/main.php
+++ b/ext/pm/main.php
@@ -197,7 +197,7 @@ class PrivMsg extends Extension {
 	private function count_pms(User $user) {
 		global $database;
 
-		$count = $database->cache->get("pm-count-{$user->id}");
+		$count = $database->cache->get("pm-count:{$user->id}");
 		if(is_null($count) || $count === false) {
 			$count = $database->get_one("
 					SELECT count(*)
@@ -205,7 +205,7 @@ class PrivMsg extends Extension {
 					WHERE to_id = :to_id
 					AND is_read = :is_read
 			", array("to_id" => $user->id, "is_read" => "N"));
-			$database->cache->set("pm-count-{$user->id}", $count, 600);
+			$database->cache->set("pm-count:{$user->id}", $count, 600);
 		}
 		return $count;
 	}