I don't know, I mean, I played the zombie mod for over a month in September with a 30 ping at the server I went to, then it became shitty with a low of 50, average of 200-500, max of 1200, which made it unplayable so I had to quit.
I don't know if I downloaded too much stuff and the school decided to nerf my internet or what. Other people had problems, and the internet company came to the school about 3 weeks ago to fix the internet, but it did absolutely nothing for my ping. But at least this is playable most of the time. CS Zombies wasn't (125+ms kick where I played).