I own some big busy site and yes i face problem now.
I do have around 1500 users online in average and site works super fast and even when i have 2000 server online site works good and server loads are normal .
But in certain hours each day my server loads are very high like 150 . And cpu usage are 95% and site loads very slow. I checked the traffic and it is too low than our busy hours.
I checked the ssh with top

I got this result , how can i prevent this? It is happening each day for particular hours and loads are very high for 5 hours even traffic are low.
My atop result
