The mt4 trading terminal has nothing to do with the speed at which your orders are executed , if your orders are not executed as fast as you want them to be there`s might be a problem with your internet connection , you need to have like a relatively fast internet not like really fast connection because the mt4 trading does not require like a very high speed internet connection.
But if the problem does not lie with the internet connection , this means that the servers of the broker you`re dealing with are the cause of the problem , and to solve this problem you should contact your broker , some brokers have multiple servers and so your account might actually get transferred to a faster server .
And if changing servers did not solve your problems then you should consider changing the broker .