As I think we are all aware my efforts to speed up CiviCRM logins have only been partially successful. There is still a lag. I did a bit more digging today & I think it is the drupal cron running as a poor-man's cron.
I think if we can confirm the cron is otherwise running on staging & prod we can disable the poor man's cron & rely on scheduled crons.
I've just disabled it on staging but probably there is no other cron running on there (@Jgreen @cwdent - is there a cron on staging running the drupal cron). It looks like the command is
drush cron
https://www.drupal.org/docs/7/setting-up-cron/overview
Disabling "automated cron"
For performance reasons, or if you want to ensure that cron can only ever run from an external trigger, it may be desirable to disable the automated cron system.
You can disable it by setting the "Run cron every" value to "Never" (e.g., at Administration > Configuration > System > Cron (admin/config/system/cron).
Alternatively, in Drupal 7, you can set the 'cron_safe_threshold' variable in the {variable} table to 0. (Note that drush will assume this variable is 0 if you have left the "Run cron every" value at the default, so you will need to set it explicitly, either at admin/config/system/cron, or via drush -y vset cron_safe_threshold 0)
Another way to disable cron in Drupal 7 is to add the following line to your settings.php:
$conf['cron_safe_threshold'] = 0;
Note that this fixes the setting at admin/config/system/cron to "Never", and administrative users cannot override it.