My Minecraft frames drop dramatically every few minutes?

Basically, every 5 minutes my Minecraft goes from 50 frames to 4-10 frames. I have this problem for a few months, then it goes away and comes back a few months later. What is wrong with it and how can I fix it?

I don't really know. I might be your CPU not able to handle too much at the same time. (where you multitasking at the moment?) I'd suggest you try Optifine (a minecraft mod that highly increases your frame rate)

What kind of computer do you have? (Post your system specs)
What other programs do you have running? (Check task manager processes).