Cache Log Error Levels
The log messages in the cache drvier's is_supported calls are more suited for the debug level.
diff --git a/system/libraries/Cache/drivers/Cache_memcached.php b/system/libraries/Cache/drivers/Cache_memcached.php
index 35d9104..d2a3a48 100644
--- a/system/libraries/Cache/drivers/Cache_memcached.php
+++ b/system/libraries/Cache/drivers/Cache_memcached.php
@@ -240,7 +240,7 @@
 	{
 		if ( ! extension_loaded('memcached') && ! extension_loaded('memcache'))
 		{
-			log_message('error', 'The Memcached Extension must be loaded to use Memcached Cache.');
+			log_message('debug', 'The Memcached Extension must be loaded to use Memcached Cache.');
 			return FALSE;
 		}