It depends how you define "running well". In my example, I am used to play CS:GO on 144 fps/144 Hz monitor without ever dropping below 144 fps on 1080p with whatever settings I want.

Now when I play PUBG my fps are between 100-144 fps even on 720p and low-medium settings. My GPU GTX 1070 is not the problem. The problem is the bad optimization of the game.

Whenever I look around at a couple of builinds and there is one player inside one of the buildings, my fps drop instantly from 144-120 or lower. Just by one opponent beeing in the direction that I look at. When I see multiple opponents, this get's worse. When I play on fog or rain runs, this get's worse.

I run the game with a 7700k @ 4.8 GHz and 16 GB DDR4 2666 MHz RAM, so it's definitely not a cheap build.

If you play a lot and you got used to play the game fluently, then you will notice the heavy bouncing fps and how it affects the responsiveness of your crosshair and it's just not a great experience at all. In my case the game plays quite well, but nowhere close to what I am used to.