Quote from TeamJack
You could try going into your search bar in the start menu (Windows 7, Vista) and type "%AppData%".
OR... Open Run, and type in "C:\Users\(INSERT YOUR USER HERE)\AppData\Roaming" (Windows XP)
After you do that, open .minecraft and then click "options" (Minecraft 1.5)
Look for the thing that says "fpslimit" and change the number from 1 to a big number like 500.
Save the options text file.
awesome! I gained roughly 10fps. its running at an average of 30-35 fps now