How to limit drupal cron CPU usage? when cron is running, apache PID peaks, and blocking the server response. is it possible to limit the cron CPU usage and leave some headroom for HTTP requests?
You can use this module elysia_cron  Elysia Cron extends Drupal standard cron, allowing a fine grain control over each task and several ways to add custom cron jobs to your site.

Elysia cron is usually used in large sites that needs performance optimization.