How to reset video settings

As of csgo, there are no real configs that could really affect your fps, aside from those in the video settings, so those are the only ones that you can tweak around and test with.

Even the developers said a hardware upgrade is probably the best solution to a low fps problem.

I would say it is purely your graphix card's limit, instead of the game settings.

Hope that helped.

The server configuration files for Counter Strike Global Offensive differ from what you're used to with previous Source-based dedicated servers. The basics are covered in this article on Valve's website however I will cover the basics here;

gamemodes_server.txt

This covers the basic settings applied for each of the different game modes available in Counter Strike: Global Offensive. These settings are loaded when the server starts and applied whenever the game mode is changed.

You should not change this file manually as it will be replaced automatically by the updater in the event you patch your server after Valve have released an update, but you can use it as a basis for making changes by understanding the file hierarchy and applying it to the next configuration file:

gamemodes_server.txt

When you first install the CSGO dedicated server, this file is called gamemodes_server.txt.example and will need to be renamed. This has the same structure as the gamemodes.txt file and must remain in this structure to be read correctly. In this file you can define any custom settings you want and you can take any of the individual settings from gamemodes.txt and re-define them here in this file. When your game server is started the settings present in this file will override those loaded from the gamemodes.txt file. This is also one location that you can define your map cycle.

autoexec.cfg

This file is executed before the first map starts and can continue any individual server variables that you could otherwise provide from the command line.

server.cfg

This is your server settings file, and contains information like your server name, rcon password, maximum number of players, etc. If this file does not exist, the game server will not start.

This is not the limitation to all of the files you can create or use, however it is an overview of the ones that are required for the game server to start up to a point where people can connect and play. There are many websites that will cover each available setting in detail and even a couple of configuration file generators that will make the changes for you. As always before making changes to any configuration file, make sure you back up your existing ones first, so you can roll back any changes that you make in the future.