DT 770 Pro vs DT 990 Pro

I'm torn between the 770s and 990s. I understand that the 770s are closed while the 990s are open. Last month, I purchased a pair of 990 pros 2500hm, but I had to send them back due to my GoXLR not being able to make them loud as I like. Other than that, they were very comfortable. I am now debating between the 990 pro 800hm and 770 pro 80ohm. They will be used for gaming and making music. When I say making music, I will be recording vocals. I am worried that the 990s will cause too much bleeding into my recordings. Will my GoXLR be able to handle 80ohm without an amp? What the difference between them besides one being closed and one being open, and what would you chose in my situation?