client-server game wtf bug

[legozaur]

hello my friends on SFML.

the problem is this:
Without a sf::RenderWindow the server brakes (delay 5 ~ 50%)
With the sf::RenderWindow it works as it should (delay 0 ~ 3%)

p.s: pictures are attached.

wtf?! 

[eXpl0it3r]

Use a debugger and if needed Wireshark to track your network data.

And at least make an effort to try an explain your issue a bit more and what steps you've taken to track things down.
Also posting code in image form is not useful, do really expect people to type the code from your images?

[legozaur]

oh, exactly
the characters on the server were terribly slow compared to customers. (pictures 3-4)
when the window was added to the server, the delays disappeared (pictures 1-2)
- translucent - traffic on the server (transferred to the client)
- opaque - the movement predicted by the client (calculation by the client)