There are things like encoders that are highly threaded that can already take advantage of these cores and more and more games will in the future not to mention that you just get the ability to run more apps simultaneously more smoothly.
Can't say that I've noticed a huge difference in going from the 920 to the 980x but things overall area bit smoother and my clock rate on the 980x is just 125 MHz over the 920 but 980x has a bigger cache which probably is the thing most impacting my observations.