Navigate to your settings, then find "System"

Scrolling all the way down in your first tab; Display. You'll see "Graphics Settings", hit that

Hitting "Browse" You will then, in this instance, look for the file path to your Yakuza 3 exe. Click on it, then click "Add" in blue;

After you've successfully added Yakuza 3 or whatever it may be, you'll see it's icon. Click on it, then click "Options"

Assuming its not already, you'll want to then toggle "High Performance and click save. No restarting of the computer is necessary, your game will be ready to play as soon as you hit save!