If I get consistent 130-140 fps on PUBG with my 970 and i5 6 gen then idk what you guys are doing with your setups.
To stay on the topic though, don't overspend. These guys are talking about high-end components when in reality you don't need that at all. You can easily upgrade your CPU and graphics card (maybe RAM too if you really want to) to something mid-spec, save a lot on not having to upgrade mobo and still get a decent performance in all current and upcoming games. If you listen to these guys you'll end up spending extra 50% for like 20% boost in performance.. Just go with what Mongius has already stated that would be my best advice.
Edit: Nvm I just realised you already ordered parts, kinda feel dumb now
Out of curiosity, are you using low graphic settings?
What size resolution?
I do sometimes hit the 144 fps on PUBG but hardly does it stay there it stays more around the 100fps average. But it does drop sometimes to 40 or 60-80 depending on certain shit. The game doesn't really stay at a consistent high FPS tbh.
To get consistent 140 i went low, but generally play on ultra.
1920x1080
Might wanna look into your setup then, you're missing out big time.