diff --git a/framework/Memcache/lib/Horde/Memcache.php b/framework/Memcache/lib/Horde/Memcache.php
index 6dd8fca..75b556e 100644
--- a/framework/Memcache/lib/Horde/Memcache.php
+++ b/framework/Memcache/lib/Horde/Memcache.php
@@ -384,8 +384,8 @@ class Horde_Memcache implements Serializable
     public function lock($key)
     {
         while ($this->_memcache->add($this->_key($key . self::LOCK_SUFFIX), 1, 0, self::LOCK_TIMEOUT) === false) {
-            /* Wait 0.1 secs before attempting again. */
-            usleep(100000);
+            /* Wait 0.05 to 0.15 secs before attempting again. */
+            usleep(mt_rand(50000, 150000));
         }
 
         $this->_locks[$key] = true;