Hey thaimport2010,
Have you already tried verifying your gamefiles and updating your graphics drivers? Did you check if the game is running on the dedicated graphics card?

• Select Tropico 6 from your Steam library
  
• Either right click the game in your Library, or click the gear icon from the game's Library page on the far right.
  
• From the drop down menu, select "Properties..."
  
• Select the "Local Files" tab and click the "Verify integrity of game files..." button
  
• Steam will verify the game's files - this process may take several minutes.)