Memcached is a general-purpose memory cache server daemon. It can improve website performance by moving Drupal's standard caches out of the database and by caching the results of other expensive database operations. Acquia Cloud supports Memcached for all paid subscriptions. If you are an Acquia Cloud Professional customer, you can enable and manage Memcached for your websites. If you are an Acquia Cloud Enterprise customer, Acquia will configure your servers with an appropriate amount of memory for Memcached.