Terrible F.P.S.

**So this is the only way I know how to contact you, I haven't play minecraft in 2 months because the FPS in terrible it goes 1 to 2 rarely 5 i look on the internet and lowered every thing I can and its still terrible. but I don't download mods because I LOVE normal version. and i played that snapshot and it just and bad. please help! some advice or some thing I love this game and i want to play it please help Me!!!