Instructions
Launch "World of Warcraft," then sign into your Battle.net account.
Choose a character from the character selection screen.
Press the "Escape" button on the keyboard, then click the "Video" menu button.
Click the "V-Sync" box, located in the "Resolution" tab, to uncheck it.
Click the "Effects" tab, then move the "Video Quality" slider all the way to "Low" setting on the left side of the slider.
Click "Apply" to save the changes made. This will increase your in-game frames per second.