I don't know if it's your problem but try to do 'gfx'. Basically you change your graphics quality when the boss spawns, when all the arms die, when the 1st body dies and when the 2nd body dies. You can easily die from this as you cannot pot as you do this and it lags for a split second everytime you do it. The quickest way to do it is to start at best picture quality, then at each time you do gfx, you do 'ESC down down enter left enter' very quickly. That will drop your picture quality by one. Do it 4 times total like I have said above. Also try to use a virtual machine with windows xp, might be more stable.
