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_wincache.php b/system/libraries/Cache/drivers/Cache_wincache.php
index d749978..80d3ac1 100644
--- a/system/libraries/Cache/drivers/Cache_wincache.php
+++ b/system/libraries/Cache/drivers/Cache_wincache.php
@@ -150,7 +150,7 @@
 	{
 		if ( ! extension_loaded('wincache'))
 		{
-			log_message('error', 'The Wincache PHP extension must be loaded to use Wincache Cache.');
+			log_message('debug', 'The Wincache PHP extension must be loaded to use Wincache Cache.');
 			return FALSE;
 		}