Why can't I get more than 60 FPS in CS:GO?

Since it is now clear that your computer indeed does support the game with acceptable FPS it is definitely a problem with your VSync settings.

There are now two things left to do:

Since Windows 10 may block/override your VSync settings you should disable that option:

1. Right-click the CSGO.exe
2. Go to Compatibility
3. Check the box for Disable fullscreen optimizations

Also make sure you have VSync off in your NVidia Control Panel. It is set to adaptive by default. Change it to off in your 3D Settings if you haven't done that yet. And you probably have done that already, but also make sure VSync is set to off in your in-game settings.

Now your FPS should be fine and you can change it to whatever you like using fps_max <value> in-game or in your config.

As others stated you should tweak the in game settings, I have a gtx 980ti and still keep everything on the lowest setting just because the extra detail is not necessary. The only thing that should not be to the lowest setting is shadow quality. At it's lowest settings you do not see them and that is a major issue. Just go one level above lowest.

Also you may have noticed a wierd resolution when you see streamers online. That's because they play on a resolution lower than 1080 and in an aspect ratio that is not 16/9.

It may sound bad at first but this is the way that most pros play and it does have its advantage. What you would want to do is set your resolution to 1024xXXX or even 800x600 and set your aspect ratio to 4:3 (think of the old CRT monitors). once you have these settings you will have black bars on the left and right hand side of your screen (due to the difference in aspect ratio). Some people like to play with black bars some don't. Try out and see what you like.

In order to get rid of the black bars you will have to play in what is considered stretch mode. All you have to do is set the launch option to -fullscreen. Here is a guide that goes more into detail: https://steamcommunity.com/sharedfiles/filedetails/?id=546255142

Here is s1mple's settings, you can see he plays on a Stretched scaling: http://liquipedia.net/counterstrike/S1mple

Here is pashaBiceps' settings, he is a player who uses black bars: http://liquipedia.net/counterstrike/Pasha

With your set up you will be able to get over 100 fps, the rest is just tweaking it to whatever you feel comfortable with. This is not a game that is meant to look good, and you really wont care about the level detail when your team beats someone 16-0 in comp.

In Video settings, make sure that your FPS isn't capped, which prevents it from going higher than a certain number.