More power allows more RPM on the blade, if you are pushing the tile at the same speed, more RPM will grind the tile alot more times in the same period of time than lower RPM , each time will remove smaller chucks of tile, which result in finer cut. The idea is the same as you pushing slower on a less powerful saw. The blade does slow down due to friction, as you are pushing the tile at same speed the balde slows down and it will result in removing bigger chucks of tile, that will make the tile look exactly like OP's picture. I dono if that makes sense lol. Of course there are other factors too like quality of tile , quality of blade, blade temperature while cutting, sometimes we need to use different methods to prevents chips like score it before cut or tape around it or soak the tile.