So summing up, a platform change to i7 8700k (cpu, motherboard, ram) would cost over $500 and bring 15%performance boost top.
However for $450-500 you can get a 1070 and get 40% improvement in games.
So summing up, a platform change to i7 8700k (cpu, motherboard, ram) would cost over $500 and bring 15%performance boost top.
However for $450-500 you can get a 1070 and get 40% improvement in games.
~30% on average
~10% would be the difference between the 8700k and 7700k
The theoretical 10-15% for cpu upgrade only really applies if your gpu/resolution can take advantage of that extra performance. With a 970 I would expect minimal gains with a cpu upgrade.