Laggy sfml Moving object, how to fix ?

[Redee]

Have main game developing question maybe at all time about gameLoop...

I wrote this C++ code with Sfml using this article >>
http://gafferongames.com/game-physics/fix-your-timestep/

Then was begun some tests.
And problem is !!!

Again and again I see a little bit LAGGY if we see some more time at movObject.
What my wrong ?
Please specify how to fix and achieve SMOOTH moving.

Here sources (MSVS) >>
https://github.com/Redee/Moving-object-Cpp-test
mirror >
https://www.dropbox.com/sh/390nvshzexxirgs/AAAH0E-NzzxWuz3HCfbuBtIUa
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Here main code to easy fast read > http://pastebin.com/he8TMHgi

Thanks in advance!