To know if it'll be a bottle neck need the resolution you want to run at and the refresh rate.
1080p you may hit a bottle neck but it will be eventually but only at really high frames rates game dependant of course but if you watch the vidoes you are hitting frame rates 100+ and even higher 200+ for e sports titles
1440p less likely especially for triple a titles
4k the great equaliser you probably wouldn't notice a difference between 6500 and 6700.
so yeah go ahead and upgrade i'm running a 1070 on 4790k at 1440p without any problems