Minecraft has horrible lag when it shouldnt?

I have 8 gb of ram

an amd fx 8320 8-core processor

and a gtx 760

when i first got this computer it ran at 200 fps but two days later it won't go over 14 also i know its not vsync

Have you tried going to the game options and set the FPS to unlimited? Also, try updating the game so it will re-download the JAR file. Do you have mods installed or anything? Sometimes it could cause lag. Try updating the jar file so that it will download a clear and fresh new Jar file.

Download Optifine and install it to your Minecraft client, it allows you to change a lot more settings within the game as well as boosting your FPS.