/wp-admin/admin-ajax.php is very slow. on the managed wordpress ultimate plan, it was taking over 5 seconds. yes, 5 seconds to submit any empty request and get back a zero. it was like admin-ajax.php was connected to a 300 baud modem and pulse dial phone that would call the server in order to receive the zero.
on the staging website is was taking 1.1-1.2 seconds. switching to the cpanel ultimate shared hosting for the php7 upgrade, it was taking 1.2-1.5 seconds. with another web hosting provider, it was taking 0.8-0.9 seconds. i would suspect a direct call to /wp-admin/admin-ajax.php to take 0.3 seconds.
anyone have an advice? anyone seen better response of admin-ajax.php on the busing hosting plans or the new 4th tier of the cpanel hosting plans? so far the staging website has been the fastest server out of all the godaddy plans. i disabled the wordpress heartbeat api.