In a nutshell, yes there is a big difference. It depends what type of system you'll be running? They both will need different types of motherboards. The 5600G has integrated graphics while the 1900X will need a GPU. The 1900X has a TDP of 180w while the 5600G is 65w making it much more energy efficient. The 5600G is a much newer cpu. The 5600G is faster but the 1900X has more cores/threads.