You are assuming it's a hardware issue. What you haven't said is that you have every setting including nvidia grass detail set for ultra, with 16x AA, while streaming 1080p video and have 10 or more tabs of Chrome open.
Or, more likely, you watched a couple of YouTube videos with a similar system and they were getting 120+ fps and you don't, so of course there is something wrong. Well there is, and the answer is quite simple. You watched YouTube videos. The pc's used in those videos are stripped of anything like AV, malwarebytes, office, Adobe, email, Cortana, and any other possible cpu impacting program in startup. They'll also tailor their nvidia settings by using pre-rendered frames set at 1,not default 3. They'll also turn down grass detail (nvidia control panel) and limit things like viewing distance. They'll also surf the internet looking for any and all tweaks, bug fixes, performance enhancements script debuggers, mods etc that'll jack up the fps.
Your hardware is fine, the fps you are getting is normal, you just haven't done the homework required to get a passing grade.
Google : GTA 5 tweaks
https://youtu.be/zazjXi6GFak