Need more information please;
What resolution and Hz is your monitor?
What games are you seeing frame drops, what are the FPS?
What configuration and speed is your RAM, for example 1x8gb 2133mhz or 2x4gb 3000mhz?
What is your current GPU?
What make and model is your PSU?
A 1070 is a good choice for your monitor. Your RAM is fast enough and can run in dual channel mode but for that game to not have any stuttering you really wanted 16gb.
However 600w tells me nothing. I need make and model. There is a huge difference between low and high quality psu’s and you don’t want to risk adding a new gpu if the psu should also be changed.