Worth Upgrading?

[byVinq]

My Current Build is :
amd fx 8350
980ti OC
256gb SSD
2TB HDD
16gb DDR3

I was just wondering, i play games like pubg csgo etc and am looking to upgrade my CPU, wondering how much a difference i could expect from that kind of upgrade and also if im better getting the i5 8600k or i7 8700k, as from what i have seen they're performance is similar in games, im also open to other CPU's if anybody has any better idea's, looking to spend no more than £600 for ram mobo and CPU ( Since it will all need replaced being old gen ). Just looking for some input to help me make a decision, anything is appreciated

 

[byVinq]

Okay thanks for the inputs guys i've come to the conclusion that im going to get the i5 and that will leave me enough money spare to get myself a h110 and hopefully push the CPU to 5Ghz+, i could get the i7 but i wouldn't have the cooling to overclock it so for the price i think the overclocked i5 will outperform the stock i7 in games considering they are neck and neck in gaming @5Ghz, of course there are some games that will take advantage of the extra threads of the i7 but for me i think the i5 will perform to a high enough standard to keep me happy in the titles where the 8700k may outshine it slightly with the extra threads. The money i save on the i7 is basically just for a h110.