(Minecraft, keyboard) Why does Char stop?

In Minecraft, when I press w, my character stops, so if I'm building and the w button has to spam, my character just stops, why?

It could be your keyboard. Some keyboards have a limited number of keystrokes that they can process simultaneously.

Well because of my keyboard it is not because I have already tested how many keystrokes it has. My keyboard is the Razer Blackwidow