Highest FPS?

I think the farthest I've seen someone get is around 10000 fps but that was an extremely expensive computer I got to see at a data center tour. By chance they decided to load something up on it and they just chose minecraft. Even if you got 10000 fps you wouldn't be able to see it, whatever your monitor refresh rate is, is what you can see. If you have a 60hz then 60fps is what you can see, a 240hz monitor you can see 240fps if you have a powerful enough graphics card.