I have a very easy solution! If you become one of those kids who uses their parents credit card to buy 500 dollar Gaming PC just for minecraft, you will have 200fps+! 100% legit.
I don't know if anyone's recommended changing your texture pack. Get a FPS texture pack, and see if it helps. If you've exhausted all your other options: save your server list, world data (if you have any), and texure packs in your .minecraft folder. Then, delete and reinstall Minecraft.
Well you're getting a lot of bad advice here. You shouldn't be trying to change things; you should be trying to find out what already changed to cause the problem. If your pc worked fine and now it doesn't, something has changed. Maybe you're running out of disk space, maybe someone installed a program that's causing a problem, maybe a setting was changed to a higher resolution your pc can't handle. At any rate, ignore all the suggestions that AMD sucks, that Minecraft doesn't use your video card, that you should change memory or priority settings. Don't do those things. Find out what changed on your computer and fix that, and your problem should be resolved. Making changes that don't help will do more damage.
That's all I had to do... I have been trying all of the advice and did not work but this, actually worked... Delete minecraft and .minecraft folder... Then reinstall it... Omg Thank you
No problem, just be careful when installing mods and certain configurations as they will completely screw up your FPS if you get the wrong ones.