This is kinda socialist if you think about it. "He's working too hard"

That's wrong, and something a kindergartner would do not an adult, you should definitely go talk to human resources about this

Honey, it's called jealousy, do your job and if others can't handle your awesomeness, than seek for another job with efficient working people.

you're overqualified, find a better job :)

It might be a inconvenience but keep and hour by hour log of what you do. This will show your supervisors that your getting your work done and that your organized.

So stop being so efficient. Your making everyone look bad, go browse some sites, play some agar or somthing

well then stop being so efficient.

At least the solution is easy, just start slacking off in moderation so your work is done slower.

Please, do yourself a favor and start looking for a different environment in which to work. There are undoubtedly companies that will appreciate your efficiency. You will do yourself a great service by continuing to search until you find one of them.

From the sound of it you work hard and get all your work done then don't do anything else so all they see you not doing anything. My advise is work slower and get done at the same time as everyone else or find other work to do when you are done.