The i5-9600K at stock clock is around 8% slower (but roughly 30% faster than your i5-4690) than Intel’s flagship i9-9900K but when both are overclocked, the 9600K closes the gaming gap to within two or three percent. Considering that the 9900K is the fastest gaming processor available, and almost twice the price of the 9600K, this is big-bang for the buck for gamers. The i5-9600K is aimed squarely at gamers who are not willing to compromise on performance but don't want to pay more than what they need. Yes, you will need a new MB socket 1150 to socket 1151 and ddr3 to ddr4 memory, but IMHO I believe you would be happy and notice a significant increase in performance.
I'm switching to the Ryzen 5 3600 too for my next build, seems like the best bang for the buck/ mid range cpu for half the price of the Intel family and very close in performance + good for multitasking.
