(Multibox) Movement

How do you make movement of characters insync when you have different speeds?

ie: Multibox 1 char will go to the right 2 units w/ 25 speed while the Multibox 2 char will go to the right 3 units w/ 50 speed - how do I make it go the same amount of units

Using C# btw

Lower all clients speed to the lowest ones speed. The server only kicks you when you're going too fast