For me it just says Gsync detected. Have never had to change settings besides Vsync and power plans. Using 391.35 driver atm win7. Suppose the later drivers reworded it wrong.
As said, gsync doesn't increase fps. Gsync just makes fps fluctuations more fluent looking.
Fps drops Depend on your setup and Windows & Nvidia settings. Power plans, vsync, Windows game bar settings & full screen optimisations (only Win10).
Whats your system specs? Heavy multi threaded games like Bf1, Fc5, Devision, Ghost Recon, Ark and more can overwhelm even modern 4c CPUs where they're commonly now reaching high 90's usage.
Ram is another factor. 16GB ram is recommended in these types of games with beefy GPUs with lots of Vram. 8GB ram brings on heavy pagefile and hdd activity. SSDs do help bottlenecks in this regard but more memory is much better.
GeForce Experience can also cause problems if allowed to 'optimise' as usually it chooses settings it thinks is best but not always. Like too much or inappropriate antialiasing method and use of Game Works in effects and shadows that a particular game might have bugs with.
Then there's Nvidia drivers and their own problems.
PCs can cause a lot of headaches especially now Win10 has made things more difficult by updating/changing settings as it sees fit. ie; introducing Game Bar / Fullscreen Optimisations and problems it caused (Csgo + Overwatch) People found out how to disable these settings only for them to turn back on next update lol
Pc can be a shambles but its worth it.