diff --git a/phpBB/docs/CHANGELOG.html b/phpBB/docs/CHANGELOG.html
index ca2ac55ecb..90ff74a2b1 100644
--- a/phpBB/docs/CHANGELOG.html
+++ b/phpBB/docs/CHANGELOG.html
@@ -92,7 +92,7 @@
 		<li>[Fix] Sorting by author or subject on viewtopic now preserves the order. (Bug #44875)</li>
 		<li>[Fix] Correctly determine writable status of files on Windows operating system. (Bug #39035)</li>
 		<li>[Feature] Backported 3.2 captcha plugins.</li>
-		<li>[Feature] Introduced new ACM plugins: null</li>
+		<li>[Feature] Introduced new ACM plugins: null, memcache.</li>
 	</ul>
 	<a name="v304"></a><h3>1.ii. Changes since 3.0.4</h3>
 
diff --git a/phpBB/includes/acm/acm_memcache.php b/phpBB/includes/acm/acm_memcache.php
new file mode 100644
index 0000000000..1fe9218104
--- /dev/null
+++ b/phpBB/includes/acm/acm_memcache.php
@@ -0,0 +1,419 @@
+<?php
+/**
+*
+* @package acm
+* @version $Id$
+* @copyright (c) 2005 phpBB Group
+* @license http://opensource.org/licenses/gpl-license.php GNU Public License
+*
+*/
+
+/**
+* @ignore
+*/
+if (!defined('IN_PHPBB'))
+{
+	exit;
+}
+
+if (!extension_loaded('memcache') || !defined('PHPBB_ACM_MEMCACHE_HOST'))
+{
+	// Memcached will not work, include the null ACM at least the
+	// board will still work.
+	// @todo Could change this for a simple error though.
+	require("${phpbb_root_path}includes/acm/acm_null.$phpEx");
+
+	return;
+}
+
+if (!defined('PHPBB_ACM_MEMCACHE_PORT'))
+{
+	define('PHPBB_ACM_MEMCACHE_PORT', 11211);
+}
+
+if (!defined('PHPBB_ACM_MEMCACHE_COMPRESS'))
+{
+	define('PHPBB_ACM_MEMCACHE_COMPRESS', false);
+}
+
+/**
+* ACM for Memcached
+* @package acm
+*/
+class acm
+{
+	var $vars = array();
+	var $is_modified = false;
+
+	var $sql_rowset = array();
+	var $sql_row_pointer = array();
+	var $cache_dir = '';
+
+	var $memcache;
+	var $flags = 0;
+
+	/**
+	* Set cache path
+	*/
+	function acm()
+	{
+		global $phpbb_root_path;
+
+		$this->memcache = new Memcache;
+		$this->memcache->connect(PHPBB_ACM_MEMCACHE_HOST, PHPBB_ACM_MEMCACHE_PORT);
+		$this->flags = (PHPBB_ACM_MEMCACHE_COMPRESS) ? MEMCACHE_COMPRESSED : 0;
+
+		$this->cache_dir = $phpbb_root_path . 'cache/';
+	}
+
+	/**
+	* Load global cache
+	*/
+	function load()
+	{
+		// grab the global cache
+		$this->vars = $this->memcache->get('global');
+
+		if ($this->vars !== false)
+		{
+			return true;
+		}
+
+		return false;
+	}
+
+	/**
+	* Unload cache object
+	*/
+	function unload()
+	{
+		$this->save();
+		unset($this->vars);
+		unset($this->sql_rowset);
+		unset($this->sql_row_pointer);
+
+		$this->vars = array();
+		$this->sql_rowset = array();
+		$this->sql_row_pointer = array();
+
+		$this->memcache->close();
+	}
+
+	/**
+	* Save modified objects
+	*/
+	function save()
+	{
+		if (!$this->is_modified)
+		{
+			return;
+		}
+
+		$this->memcache->set('global', $this->vars, $this->flags, 2592000);
+
+		$this->is_modified = false;
+	}
+
+	/**
+	* Tidy cache
+	*/
+	function tidy()
+	{
+		// cache has auto GC, no need to have any code here :)
+
+		set_config('cache_last_gc', time(), true);
+	}
+
+	/**
+	* Get saved cache object
+	*/
+	function get($var_name)
+	{
+		if ($var_name[0] == '_')
+		{
+			return $this->memcache->get($var_name);
+		}
+		else
+		{
+			return ($this->_exists($var_name)) ? $this->vars[$var_name] : false;
+		}
+	}
+
+	/**
+	* Put data into cache
+	*/
+	function put($var_name, $var, $ttl = 2592000)
+	{
+		if ($var_name[0] == '_')
+		{
+			$this->memcache->set($var_name, $var, $this->flags, $ttl);
+		}
+		else
+		{
+			$this->vars[$var_name] = $var;
+			$this->is_modified = true;
+		}
+	}
+
+	/**
+	* Purge cache data
+	*/
+	function purge()
+	{
+		// Purge all phpbb cache files
+		$dir = @opendir($this->cache_dir);
+
+		if (!$dir)
+		{
+			return;
+		}
+
+		while (($entry = readdir($dir)) !== false)
+		{
+			if (strpos($entry, 'ctpl_') !== 0 && strpos($entry, 'tpl_') !== 0)
+			{
+				continue;
+			}
+
+			$this->remove_file($this->cache_dir . $entry);
+		}
+		closedir($dir);
+
+		$this->memcache->flush();
+
+		unset($this->vars);
+		unset($this->sql_rowset);
+		unset($this->sql_row_pointer);
+
+		$this->vars = array();
+		$this->sql_rowset = array();
+		$this->sql_row_pointer = array();
+
+		$this->is_modified = false;
+	}
+
+
+	/**
+	* Destroy cache data
+	*/
+	function destroy($var_name, $table = '')
+	{
+		if ($var_name == 'sql' && !empty($table))
+		{
+			if (!is_array($table))
+			{
+				$table = array($table);
+			}
+
+			foreach ($table as $table_name)
+			{
+				// gives us the md5s that we want
+				$temp = $this->memcache->get('sql_' . $table_name);
+
+				if ($temp === false)
+				{
+					continue;
+				}
+
+				// delete each query ref
+				foreach ($temp as $md5_id => $void)
+				{
+					$this->memcache->delete('sql_' . $md5_id);
+				}
+
+				// delete the table ref
+				$this->memcache->delete('sql_' . $table_name);
+			}
+
+			return;
+		}
+
+		if (!$this->_exists($var_name))
+		{
+			return;
+		}
+
+		if ($var_name[0] == '_')
+		{
+			$this->memcache->delete($var_name);
+		}
+		else
+		{
+			$this->is_modified = true;
+			unset($this->vars[$var_name]);
+
+			// We save here to let the following cache hits succeed
+			$this->save();
+		}
+	}
+
+	/**
+	* Check if a given cache entry exist
+	*/
+	function _exists($var_name)
+	{
+		if ($var_name[0] == '_')
+		{
+			return true;
+		}
+		else
+		{
+			if (!sizeof($this->vars))
+			{
+				$this->load();
+			}
+
+			return isset($this->vars[$var_name]);
+		}
+	}
+
+	/**
+	* Load cached sql query
+	*/
+	function sql_load($query)
+	{
+		// Remove extra spaces and tabs
+		$query = preg_replace('/[\n\r\s\t]+/', ' ', $query);
+		$query_id = sizeof($this->sql_rowset);
+
+		if (($result = $this->memcache->get('sql_' . md5($query))) === false)
+		{
+			return false;
+		}
+
+		$this->sql_rowset[$query_id] = $result;
+		$this->sql_row_pointer[$query_id] = 0;
+
+		return $query_id;
+	}
+
+	/**
+	* Save sql query
+	*/
+	function sql_save($query, &$query_result, $ttl)
+	{
+		global $db;
+
+		// Remove extra spaces and tabs
+		$query = preg_replace('/[\n\r\s\t]+/', ' ', $query);
+		$hash = md5($query);
+
+		// determine which tables this query belongs to
+		preg_match('/FROM \\(?(\\w+(?: \\w+)?(?:, ?\\w+(?: \\w+)?)*)\\)?/', $query, $regs);
+		$tables = array_map('trim', explode(',', $regs[1]));
+
+		foreach ($tables as $table_name)
+		{
+			if (($pos = strpos($table_name, ' ')) !== false)
+			{
+				$table_name = substr($table_name, 0, $pos);
+			}
+
+			$temp = $this->memcache->get('sql_' . $table_name);
+
+			if ($temp === false)
+			{
+				$temp = array();
+			}
+
+			$temp[$hash] = true;
+
+			$this->memcache->set('sql_' . $table_name, $temp, $this->flags, $ttl);
+		}
+
+		// store them in the right place
+		$query_id = sizeof($this->sql_rowset);
+		$this->sql_rowset[$query_id] = array();
+		$this->sql_row_pointer[$query_id] = 0;
+
+		while ($row = $db->sql_fetchrow($query_result))
+		{
+			$this->sql_rowset[$query_id][] = $row;
+		}
+		$db->sql_freeresult($query_result);
+
+		$this->memcache->set('sql_' . $hash, $this->sql_rowset[$query_id], $this->flags, $ttl);
+
+		$query_result = $query_id;
+	}
+
+	/**
+	* Ceck if a given sql query exist in cache
+	*/
+	function sql_exists($query_id)
+	{
+		return isset($this->sql_rowset[$query_id]);
+	}
+
+	/**
+	* Fetch row from cache (database)
+	*/
+	function sql_fetchrow($query_id)
+	{
+		if ($this->sql_row_pointer[$query_id] < sizeof($this->sql_rowset[$query_id]))
+		{
+			return $this->sql_rowset[$query_id][$this->sql_row_pointer[$query_id]++];
+		}
+
+		return false;
+	}
+
+	/**
+	* Fetch a field from the current row of a cached database result (database)
+	*/
+	function sql_fetchfield($query_id, $field)
+	{
+		if ($this->sql_row_pointer[$query_id] < sizeof($this->sql_rowset[$query_id]))
+		{
+			return (isset($this->sql_rowset[$query_id][$this->sql_row_pointer[$query_id]][$field])) ? $this->sql_rowset[$query_id][$this->sql_row_pointer[$query_id]][$field] : false;
+		}
+
+		return false;
+	}
+
+	/**
+	* Seek a specific row in an a cached database result (database)
+	*/
+	function sql_rowseek($rownum, $query_id)
+	{
+		if ($rownum >= sizeof($this->sql_rowset[$query_id]))
+		{
+			return false;
+		}
+
+		$this->sql_row_pointer[$query_id] = $rownum;
+		return true;
+	}
+
+	/**
+	* Free memory used for a cached database result (database)
+	*/
+	function sql_freeresult($query_id)
+	{
+		if (!isset($this->sql_rowset[$query_id]))
+		{
+			return false;
+		}
+
+		unset($this->sql_rowset[$query_id]);
+		unset($this->sql_row_pointer[$query_id]);
+
+		return true;
+	}
+
+	/**
+	* Removes/unlinks file
+	*/
+	function remove_file($filename, $check = false)
+	{
+		if ($check && !@is_writable($this->cache_dir))
+		{
+			// E_USER_ERROR - not using language entry - intended.
+			trigger_error('Unable to remove files within ' . $this->cache_dir . '. Please check directory permissions.', E_USER_ERROR);
+		}
+
+		return @unlink($filename);
+	}
+}
+
+?>
\ No newline at end of file