Is allocating too much memory to Hexxit (minecraft) bad?

I just did it and it is still choppy and I want to know if it is bad to give it more (I have 8 gb computer and I gave it 4gb)

4 is more then enough memory (Ram) for Hexxit. It might be the processor on your computer or graphics card. Might have to change your settings lower the resolution the graphics quality. Just don't set it to fancy. And no it's not bad it just might make your computer run slower if it uses the other portion of the memory(ram) for other programs.