Best FPS Booster for minecraft?

You can install Optifine. But I would recommend installing a launcher. If you have a premium account you can download the Lunar Client or the Badlion Client, they help a lot with the FPS thing.
Another cient that you can download is the J3Ultimate, a nice PVP client that boots your FPS and is la light one. (Well, technically is a mod not a client, but meh).
You can also download a nice 8x8 - 16x16 texture pack.

Optifine is always the best option, it lets you modify many things in terms of graphics to improve the fps

buy an new computer ? XD beacose with the time minecraft is going to use more ressource so ...

For me the Best Booster is and was Optifine otherwise i get always low FPS