Lagging real bad to the point I can not play.

My brother purchased this game a few days back and he really likes it and I enjoy playing minecraft so I had decided to buy it as well to play with him, mine and his laptop are the same and my laptop is perfectly fine so I do not get why his game function is perfectly fine and mine is not. I feel like I have wasted £18 on this game which does not even function correctly; I could have used that money for something else. Please fix this as I can not play with this lag and basically have wasted my money.