Why does Sylius or Symfony2 take so long to render pages?

Question

symfony

Installed Sylius on the server.
Launched in public mode. Processing the main page (without loading into the browser) with default settings is 7-10 seconds.
Sylius is developed on the Symfony 2 framework and has over 3000 commits on github, a large community, about 150 contributors and a high rating on GitHub .
Are all these people developing such a brake product? Tried deploying sylius on 2 different computers. Almost the same result everywhere.
Can a modern framework produce such a result in 7-10 seconds of page processing (I repeat without loading it into the browser, that is, it takes more time to load scripts, pictures, styles, html code)?
What's the catch?
Explain, please.
Another example is with the symphony. On one of my current projects, the page can be processed by the server for about 3 seconds or more (without loading it into the browser). When you increase the functionality, the page load of course increases. Why would the community develop such a slow product? I have seen many large portals on the Internet, the pages of which are processed in no more than 1 second. Is their development group smarter than the entire Symphony community put together?
There are no questions about the architecture of the framework. The question is only to the speed of page processing. I'm at a loss.
Another story with sonata admin bundle. After installing it, I checked the page load performance. The response was great, after which I deleted it in horror.
Is this the case for everyone or is it just me? I do not understand.
MB do I have crooked hands?
Thanks in advance for your reply.
UPD.
found a site deployed on Sylius, the page load of which is no more than 1 second. Why does it come out like this? I don't understand anything.
UPD2.
Partially understood. Transferred site files from one storage to ssd, thereby reducing page processing speed.
Sylius: Before:
6-8 sec - prod environment. About 1 minute - dev environment.
Now: 3 sec - prod environment. 6-8 sec - dev environment.
But the results are still not so hot. On the demo site above, Sylius takes less than a second to load.

Answer 1

Specify which OS you are deploying to, PHP version, whether there are opcode caches, etc. is an optimized bootloader built, perhaps some gain can be obtained due to better compilation of the dependency container ... You can also try to run it on HHVM.
And what does the profiler show in the dev environment?

Answer 2

Download the profiler and see what slows down the download. Guessing on coffee grounds makes no sense. Maybe you are running your application on a dandy.

Answer 3

My profiler shows that most of the time templates are generated.
The standard assembly of Silius is installed, on a local wheelbarrow (xampp, win7, ssd and good hardware parameters). Can this point be somehow corrected, and if so, how?

Answer 4

I confirm that some kind of crap happens for ~ 7 seconds of loading, apparently you need to pull some command to optimize the internal cache, or something else ...

Answer 5

With the help of check_configuration.php I found out about APC.
Installed APC accelerator - everything flew much faster.