I found out the problem. I have Time Warner cable and am located in the Northeast region. I was LEASING a modem from TWC and purchased a modem today (Netgear N600). Halo 5 is now running smooth as ever. No lag, no more watching people running into place into walls. Advice: Buy a new modem! It will save you bill in the long run anyway. These outdated modems that timewarner has are complete garbage.