I<m having this problem now it's been almost 2 weeks, and it's not good. Every day, multiple times a day the server goes down because of the load going overboard. Now I have a very few plugins that may be causing this. I have a cron job that keeps swallowing all the resources! Don't know which one it is, but deacivated almost everything that has automated things happening. My next move is to disable Defender (as it has caused server load issues in the past).
The second file that keeps popping up is admin-ajax.php. I have it showing up in the processes almost ALL THE TIME!
I'm at a loss as to why it keeps showing up. I heard it's for trackbacks and pings. I deactivated it as recommended in Defender (I believe). I really don't know how to resolve this issue and it has been taking hours of my day everyday for the past 2 weeks.
Your help is truly appreciated.