CPU Full access WP Admin

Hi All,

I got problem when I access Admin Page of my WordPress site. I used VM in Google Cloud Platform with 4 CPU and 8GB RAM. I got 300/hit visitor (Google Analytic) and CPU was fine, until I access WP-Admin. Suddenly CPU Usage become 100% for 1-2 minutes, every 1 click in WP-Admin, CPU will full for 1-2 minutes. When I publish post, It I got “Connection Lost” until my CPU come back normal. I have seperated VM for Web and DB but in same region so latency would be a problem. Can you guys help me?

My theme : Avada Theme
My plugins :
– All In One Schema.org Rich Snippets
– Accelerated Mobile Pages
– Anti-spam Pro
– App Banners
– Easy Social Share Buttons for WordPress
– Featured Image In Rss Feed
– FormCraft
– FormCraft Multi Page Forms Add-On
– Fusion Builder
– Fusion Core
– Heartbeat Control
– Instant Articles for WP
– JSON API
– Limit Login Attempts
– Ninja Popups
– Nofollow for external link
– PixelYourSite PRO
– SendGrid
– SSL Insecure Content Fixer
– TinyMCE Advanced
– TotalPoll
– WP Rocket
– WP User Avatar
– WP Viral Quiz
– Yoast SEO Premium

My Post : 4038

The page I need help with: [log in to see the link]