Well, you do have less FPS than some youtuber and it's because of your CPU.
But, here's one thing you have in common, your 350FPS and his 700FPS are the same. Let me explain.
Your monitor is at most a 144Hz, probably even less, that means it can refresh 144 times each second, thus displaying 144FPS.
Having FPS above that is not effective, because it's not getting displayed on the screen.
Yes, it does improve smoothness a little bit, maybe when going from 150 to 300, but 300 to 700? I don't think you'll see a difference.
If you want to test your GPU, download a real game that has a benchmark, like Tomb Raider.