Steps:
#1: Open up the folder containing the Minecraft.exe file.(located in .minecraft bin)
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#2: Right click and make a new text document or .txt file.
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#3: Now open the text file you just created and copy and paste this to it:
@ECHO OFF
"Your java path here\javaw.exe" java -Xmx1024M -Xms1024M -jar "Your minecraft path here\minecraft.exe"
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#4: Where you see the -Xmx1024M and -Xms1024M you can change it to as much RAM as you want.(If you don't know your RAM go to-Start>search dxdiag and look at memory and it will say how much RAM you have. Minecrafts Default RAM is about 490.Don't type it as GB or it wont work!

RAM Key-
1GB- 1024
2GB- 2048
3GB- 3072
4GB- 4096
5GB- 5120
6GB- 6144
7GB- 7168
8GB- 8192
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#5: Then go to file; Save As, and make sure to save it as a .bat file. For example, I named mine memory.bat
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#6: Run Minecraft and check your fps and if you did it right your fps should be increased pretty good.