I multiple droplets. All are created with Serverpilot and memcached

Two of them is $10 size.

One of the $10 has three websites up and running. And, while I check Google page speed, no problem with server response. Although CPU usages goes upto 100%.

Another $10 droplet with only one website which gets 4000 hits a day. CPU usages never hit more than 40%. Google says sever takes 1.2 sec to respond. This droplet is using Digital Ocean backup system.

My question is :-

DO backup is slowing down server?

In one website droplet, initially I had forget to install memcached. I just connected to serverpilot, installed all resources, created a apps, moved website in and start running the website. Latest I got remember about memcached, so I installed.

Will this have a impact on performance?

Or there is another reason?

I have checked with

top

nothing seems weird. In both $10, everything is equal and similar. Then why the second droplet with one website running so slow?