PHP scripts typically run as a single build-up tear-down process. This is problematic when running batch operations, such as the Drupal cron run. For larger sites, cron will often time out or run out of memory thus failing to complete all maintenance tasks. Cron MT increases efficiency and reliability by utilizing PHP's "Process Control" extension available to Unix-like platforms. By forking the cron process a configurable number of times, Cron MT is able to execute each hook_cron() implementation in parallel allowing the system to distribute the load across its multiple CPUs.
