Game launch options can be used to change game settings before running the game.
Launch options allow the user to supercede inner settings of the game.

The launch options underneath are the most effective launch options promising a significant FPS boost. I am using these myself and has experienced a generous increase in FPS.
WARNING - YOUR NEED TO ADJUST THE SETTINGS TO YOUR EQUIPMENT

-freq 240 -d3d9ex -novid -no-browser +mat_queue_mode 2 +fps_max 0 +cl_interp_ratio 1 +cl_interp 0.031 -tickrate 128 +cl_cmdrate 128 +cl_updaterate 128 +cl_forcepreload 1

1. Right-click on Counter-Strike: Globel Offensive under the Library in Steam and select Properties.
   
   
2. Under the General tab click the Set launch options button.
   
   
3. Enter the launch options you wish to apply (be sure to separate each code with a space) and click OK.
   
   
4. Close the game’s Properties window and launch the game.

• -full
  The game will start in full-screen mode.
  
  
• -window
  The game will start in the regular window. Commands with similar effect: -windowed, -startwindowed, and -sw
  
  
• -noborder
  he game window won’t have edges.
  
  
• +cl_showfps 1
  Your FPS will be displayed at the top right corner.
  
  
• -high
  Use this launch option to set up CS 2 high priority process.
  
  
• -nojoy
  Switching off joysticks, joystick support.
  
  
• -console
  The option will force console opening once the game is started.
  
  
• -language English
  Interface language customization for CS 2. In this case, the English language is indicated, however, you can use any other language you like.
  
  
• -threads
  Here you should enter the number of cores your processor has, however, the CS2 specifies the settings your processor has on its own, thus this command is useless.
  
  
• +r_drawparticles 0
  Launch option disables particles animation, graphics will get worse, but, might improve performance.
  
  
• -nod3d9ex1
  TCommand for switching off d3d9ex mode technology. It is worth trying this command, since game performance may be improved as well.
  
  
• -autoconfig
  This command lets you restore config file settings to deafult.
  
  
• +exec file name
  Launch option that launching the config with game settings (.cfg). The file should be placed in the folder "Steam\SteamApps\common\Counter-Strike Global Offensive\cs2\cfg".
  
  
• +mat_disable_fancy_blending 1
  This command is for fancy blending, and degrades the quality of textures, as a result, the performance is increasing.
  
  
• -r_emulate_g
  OpenGL emulation is working only for Windows, can increase FPS.
  
  
• -softparticlesdefaultoff
  Rendering particles settings for CS2.
  
  
• -nopreload
  Cancels models, files and textures pre-loading.
  
  
• -nohltv
  Switches off all GOTV and Source TV opportunities.
  
  
• -limitvsconst
  Limits number of vertex shaders up to 256.
  
  
• -forcenovsync
  Switches off Vsync technology.
  
  
• +violence_hblood 0
  Command, which eliminates the elements of violence in the game, particularly blood, and low violence.
  
  
• +r_dynamic 0 / 1
  Switches on/off dynamic lighting.