[New Vegas] Companions lagging my game? +achievement not unlocking

I recently recruited Boone as a companion in Fallout New Vegas. Now suddenly the game has been really laggy. Any idea why? I also had an instance where just looking at him would cause REALLY messed up graphics and a frozen screen.

Also, The 'Old Buddy Old Pal' achievement didn't unlock for me. I'm thinking this was because I had used godmode to get out of Caesars Legion alive, but it was disabled at the time of recruiting Boone.