josh_huang :
Rexper :
Bottlenecking doesn't work like that. It depends on the situation and it is inevitable, so it is basically pointless to worry about.
Instead, consider if your CPU can perform up to 100FPS in the games you play. An R5 1600/i5 should take care of that, but it depends on the games.
What CPU do you have now? If it is able to perform up to 100FPS with your current GPU at a low resolution, it will be able to do it with new monitor + GPU.
https://pcpartpicker.com/forums/topic/214851-on-cpugpu-bottlenecking-in-games
I play Tom Clancy's Ghost Recon at 35 fps at medium graphic setting and playerunkown's battleground at 70 fps at very low setting. The ultimate goal is to play most RPG/FPS games (e.g. AC origins and COD WW2) at ultra graphic setting on 1440p 100Ghz at 60+ FPS.
I am not with my PC right now and cannot check what I have, but it's an i5 which I bought in 2012 January so I believe it would be very old.
I'd be aiming more towards your monitor's refresh rate, 100hz/100FPS, rather than just 60. WIth your current CPU and GPU, decrease your in game resolution temporarily down to ~400p. If the FPS you receive in those games fine, or near 100FPS, your CPU will be good.