External Frame Buffer (XFB) should never be set unless a game absolutely requires it (like if the Dolphin Wiki recommends it or someone tells you it fixes a specific issue). Otherwise, you're just playing around with settings that are more likely to do something you don't want it to do.
Tell us which game(s) you've tried to play, that's important to know as well. Have you tried enabling VSync either through Dolphin or your GPU drivers? If you could as well, post screenshots of all of your graphics settings so we can see what you've done.
Tell us which game(s) you've tried to play, that's important to know as well. Have you tried enabling VSync either through Dolphin or your GPU drivers? If you could as well, post screenshots of all of your graphics settings so we can see what you've done.