When I play by myself everything runs fine and smooth, but when I am splitscreening with my brother 50% of the games suffer from severe framedrop!
Is there ANYTHING I can do to fix this?
I have this exact same problem. You can try to install disc 1 if your hard drive is big enough but I’m not sure if that will help. Kind of sucks 343 screwed over people who always played halo splitscreen
I will install it and see if anything changes. Thank you 
Splitscreen and Halo goes together like milk and chocolate, and I would cry if it can’t be fixed!
Yes dont play splitscreen, the Xbox is 7 years old so it cant handle splitscreen very well when a game looks as good as Halo 4 does.