Im a little late to the party but ill add something that may be of great value.
As now a days FPS matters a lot, i personally have a 240hz but i cant fully enjoy it... because...
I also own a 1080ti and a 3770k, and that processor has always been the very best at everything, and therefore i havent been in any need of upgrading since 2013.
But today i realized, that EVERYGAME is capped at 185FPS.
So i was checking, done Overclock and stuff.
For some reason, i with or without Overclock i cannot seem to get past 185FPS, but CPU usage is always at 100% i tried 3.5 3.9 4.2 and 4.5, and 4.6Ghz they are all the same in regards of gaming performance, at least for the games i played.
Tried any resolution, even 720p at lowest and it will always be 185, therefore it must be the CPU.
So, i wouldnt recommend trying to overclock way beyond the limits, i would recomend 4.2Ghz is great, amazing performance and low temps...
and upgrade whenever possible, as your 1080ti and do much more than you may think it can actually do...
hope it helps mate.
ALSO: if you think my Bottleneck isnt the CPU and there is sort of stupid glitch, PLEASE let me know LOL.