I logged in the apache processes when this drop happens and found a common thing in both the logs I got.
8-0 24041 0/1680/1680 _ 52.13 0 69721 0.0 4.21 4.21 18.104.22.168 GET /malloc.php HTTP/1.0
Can anyone give me some information about malloc.php associated with XenForo?
When I restore a backup the logs go off mate.
It does happen once or twice a day at different timings.
I have addons installed, I have attached a screenshot of my addon list and cron tasks.
thanks for the prompt response guys!