I upgraded my 2500k last year (to a Ryzen system) and the extra cores are very nice sometimes but honestly the biggest improvement was the fact that I also went

I upgraded my 2500k last year (to a Ryzen system) and the extra cores are very nice sometimes but honestly the biggest improvement was the fact that I also went from 8GB RAM to 16GB. There were a couple of games that benefited substantially from faster memory (Rise of the Tomb Raider, Fallout 4) but generally not so much the actual CPU performance.