Store gets very slow after logging to the control panel or making a change in it

We have a store OC3 using Journal 3 as a theme, PHP 7, dedicated server that has many websites,
after logging into the control panel, the store gets very slow for one or two minutes, even it gives 500 internal server error, sql server gets over 100% and many processes are being created for the same user which is mobilof+,
this is a screenshot of top command in the server,
the user mobilo+ is the user related to the website, although no real traffic on the website at that moment, there are many processes

http://www.galatakulesi.org/test/screenshot2.jpeg

I couldn't figure what is happening, Theme and SASS cache is being active in OpenCart,

Who can provide support?
Thanks everyone

Hello There,

I can surely help you with this task. Please mail me at: troy.cis20@gmail.com and skype me: cis.troy to discuss it more.

Looking forward!

Regards
Troy

Hello ,
Greetings!

I can assist you further
Add me on Skype - deepvyas71

Best Regards
Deep

Hi there,

We should be able to help with this if you still need it, would you be able to drop us an email to get an estimate?
info@antropy.co.uk

Kind regards,
Alex
www.antropy.co.uk

Hello,

Did you find the solution? If you still need assistance then you can let me know. You can find the contact details in this thread signature.