Also, check what version of java you are using, if you're using the 32-bit version that is probably the reason why you have so poor performance if you are using 64-bit Java Version 8 Update 231, try using Java Version 8 Update 51 that is Minecraft set by default to run. If you don't know how to see what version of java are you using just press F3 and on top right corner you will see version.
srdjan
Also, check what version of java you are using, if you're using the 32-bit version that is probably the reason why you have so poor performance if you are using 64-bit Java Version 8 Update 231, try using Java Version 8 Update 51 that is Minecraft set by default to run. If you don't know how to see what version of java are you using just press F3 and on top right corner you will see version.