I have an amazing pc but why can't I run Minecraft?

Minecraft, especially with mods, isn't very well optimized.

Minecraft is a surprising performance hog, especially on your CPU. 80fps really isn't all that bad. I'm assuming you are running a monitor capable of above 100Hz (120Hz? 144Hz?). The reason I ask is because you would be surprised at how many people come on Y/A asking questions like "Is 130FPS okay for a GTX 1080 running Fallout 4 maxed out at 1080p?" and then it turns out they have a 60Hz monitor so it doesn't matter even a little bit.

Also, if you are running a modded version of Minecraft, it will take a HUGE hit in performance. I've seen modded versions pushed by a GTX 1080 and a 7700k that cap out at around 50FPS.

When it comes down right to it, if Minecraft is the only game you seem to be suffering with performance, then that s not bad. Assuming you have a monitor that can take advantage of high framerates, there just isn't enough going on in Minecraft to stress about sub 80FPS framerates. Even at 1080p, there just isn't enough that could happen in between frames that would warrant any average framerate above 60FPS. Compare this to something like Overwatch where there's quite a bit that could happen in a missing frame, Minecraft just doesn't have this problem.