diff --git a/lib/Cake/Cache/CacheEngine.php b/lib/Cake/Cache/CacheEngine.php
index 7b285e041..3b1b74e67 100644
--- a/lib/Cake/Cache/CacheEngine.php
+++ b/lib/Cake/Cache/CacheEngine.php
@@ -170,7 +170,7 @@ abstract class CacheEngine {
 			$prefix = vsprintf($this->_groupPrefix, $this->groups());
 		}
 
-		$key = Inflector::underscore(str_replace(array(DS, '/', '.'), '_', strval($key)));
+		$key = preg_replace('/[\s]+/', '_', strtolower(trim(str_replace(array(DS, '/', '.'), '_', strval($key)))));
 		return $prefix . $key;
 	}
 
diff --git a/lib/Cake/Cache/Engine/ApcEngine.php b/lib/Cake/Cache/Engine/ApcEngine.php
index d9c155abb..7b93cbb0c 100644
--- a/lib/Cake/Cache/Engine/ApcEngine.php
+++ b/lib/Cake/Cache/Engine/ApcEngine.php
@@ -44,7 +44,11 @@ class ApcEngine extends CacheEngine {
  * @see CacheEngine::__defaults
  */
 	public function init($settings = array()) {
-		parent::init(array_merge(array('engine' => 'Apc', 'prefix' => Inflector::slug(APP_DIR) . '_'), $settings));
+		if (!isset($settings['prefix'])) {
+			$settings['prefix'] = Inflector::slug(APP_DIR) . '_';
+		}
+		$settings += array('engine' => 'Apc');
+		parent::init($settings);
 		return function_exists('apc_dec');
 	}
 
diff --git a/lib/Cake/Cache/Engine/FileEngine.php b/lib/Cake/Cache/Engine/FileEngine.php
index 23e043b98..16c894c7f 100644
--- a/lib/Cake/Cache/Engine/FileEngine.php
+++ b/lib/Cake/Cache/Engine/FileEngine.php
@@ -68,13 +68,16 @@ class FileEngine extends CacheEngine {
  * @return boolean True if the engine has been successfully initialized, false if not
  */
 	public function init($settings = array()) {
-		parent::init(array_merge(
-			array(
-				'engine' => 'File', 'path' => CACHE, 'prefix' => 'cake_', 'lock' => true,
-				'serialize' => true, 'isWindows' => false, 'mask' => 0664
-			),
-			$settings
-		));
+		$settings += array(
+			'engine' => 'File',
+			'path' => CACHE,
+			'prefix' => 'cake_',
+			'lock' => true,
+			'serialize' => true,
+			'isWindows' => false,
+			'mask' => 0664
+		);
+		parent::init($settings);
 
 		if (DS === '\\') {
 			$this->settings['isWindows'] = true;
diff --git a/lib/Cake/Cache/Engine/MemcacheEngine.php b/lib/Cake/Cache/Engine/MemcacheEngine.php
index 4f588bf50..4729de358 100644
--- a/lib/Cake/Cache/Engine/MemcacheEngine.php
+++ b/lib/Cake/Cache/Engine/MemcacheEngine.php
@@ -66,19 +66,21 @@ class MemcacheEngine extends CacheEngine {
 		if (!class_exists('Memcache')) {
 			return false;
 		}
-		parent::init(array_merge(array(
+		if (!isset($settings['prefix'])) {
+			$settings['prefix'] = Inflector::slug(APP_DIR) . '_';
+		}
+		$settings += array(
 			'engine' => 'Memcache',
-			'prefix' => Inflector::slug(APP_DIR) . '_',
 			'servers' => array('127.0.0.1'),
 			'compress' => false,
 			'persistent' => true
-			), $settings)
 		);
+		parent::init($settings);
 
 		if ($this->settings['compress']) {
 			$this->settings['compress'] = MEMCACHE_COMPRESSED;
 		}
-		if (!is_array($this->settings['servers'])) {
+		if (is_string($this->settings['servers'])) {
 			$this->settings['servers'] = array($this->settings['servers']);
 		}
 		if (!isset($this->_Memcache)) {
diff --git a/lib/Cake/Cache/Engine/WincacheEngine.php b/lib/Cake/Cache/Engine/WincacheEngine.php
index 6482135c1..542172c0c 100644
--- a/lib/Cake/Cache/Engine/WincacheEngine.php
+++ b/lib/Cake/Cache/Engine/WincacheEngine.php
@@ -45,10 +45,11 @@ class WincacheEngine extends CacheEngine {
  * @see CacheEngine::__defaults
  */
 	public function init($settings = array()) {
-		parent::init(array_merge(array(
-			'engine' => 'Wincache',
-			'prefix' => Inflector::slug(APP_DIR) . '_'),
-		$settings));
+		if (!isset($settings['prefix'])) {
+			$settings['prefix'] = Inflector::slug(APP_DIR) . '_';
+		}
+		$settings += array('engine' => 'Wincache');
+		parent::init($settings);
 		return function_exists('wincache_ucache_info');
 	}
 
diff --git a/lib/Cake/Cache/Engine/XcacheEngine.php b/lib/Cake/Cache/Engine/XcacheEngine.php
index 35da1810d..c5f3b430f 100644
--- a/lib/Cake/Cache/Engine/XcacheEngine.php
+++ b/lib/Cake/Cache/Engine/XcacheEngine.php
@@ -45,13 +45,15 @@ class XcacheEngine extends CacheEngine {
  * @return boolean True if the engine has been successfully initialized, false if not
  */
 	public function init($settings = array()) {
-		parent::init(array_merge(array(
+		if (!isset($settings['prefix'])) {
+			$settings['prefix'] = Inflector::slug(APP_DIR) . '_';
+		}
+		$settings += array(
 			'engine' => 'Xcache',
-			'prefix' => Inflector::slug(APP_DIR) . '_',
 			'PHP_AUTH_USER' => 'user',
 			'PHP_AUTH_PW' => 'password'
-			), $settings)
 		);
+		parent::init($settings);
 		return function_exists('xcache_info');
 	}