How to reduce TTFB?

Question

Nginx

Good afternoon.
The essence of the problem: There are different sites on the same server, on different CMS, and they have very different TTFB
DLE, IPB : 0.15-0.12 sec
Cs-cart, Open Real Estate : 0.8-2 sec
For the test, I set empty CMS, the result is the same.
What could be the problem?

Answer 1

Guys, tell me

Answer 2

I have the same problem. Who will help with advice: my website prostolinux.ru page generation lasts 1.5 seconds. On other sites it is several times less, about 0.2. I already cut down all the plugins, and changed the theme, and cleaned the database, what I just didn’t do, I just can’t figure out how to find the problem? Can someone tell me where to dig?
The code generation time is displayed in my footer. For comparison, such an informer is on the zmoe.ru site on the same server.