Since my internet connection is being very slow lately, making online play difficult, I've been gunning to get a few of those achievements in SC2 that I've never bothered with, mainly the custom game ones. This involves setting up custom games against only AI opponents.

However, even when I play these custom AI games, when there's nothing to lose and nothing to prove, I'll be lagging with myself. I even came close to getting disconnected in a few games. The only human opponent involved is myself; how can I be lagging in this sort of situation?

2 Answers 2


All games on Battle.net 2.0 (which SC2 uses) are hosted on Blizzard's servers, hence your lag. Only when you are playing in offline mode are the games hosted on your own computer. You can play offline by selecting the "play as guest" option on the right hand side of the login screen instead of completing the normal login process. If you are playing in offline mode, then unfortunately you cannot earn any achievements.

  • 1
    +1: I experienced the same issue and contacted Blizzard support - they confirmed that playing against AI needs a similar Battle.net connection as playing against another player. May 18, 2011 at 9:18

Just because you aren't connected to other computers doesn't mean that your network isn't under strain. Before you start laying the blame on Starcraft 2 itself, consider the following:

  • Are you on a wireless connection? More than once I've simply had a 'hiccup' due to my router being cheap and old (7 years now, I think?).
  • Are you on a shared wireless connection? One of the joys of living with my brother means a constant awareness of what he's doing on the network. If he's playing online games, it's usually not a big issue, but heaven help my FPS and latency should he decide to open a youtube video or shudders with shame handling torrents.
  • Is this a lag issue at all, or merely graphical frame stuttering? Either force your computer to ignore the internet (possibly hard, I realize) and play a custom game in Starcraft 2's offline mode. It's easy to check, and a good way to determine if it is the network, or if it's your computer. Alternatively, try playing Starcraft 2 from a separate computer.
  • Wait a week and try again! Sometimes, there's just something wrong with the pipes -- momentary troubles either with your provider, the battle.net servers, or any number of things. If it continues to be an issue over a longer time period, then it is more likely to not be external problems.
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    Well, I know it's my connection that's causing the problems("Since my internet connection is being very slow lately..."). I'm more confused as to how I can be encountering lag in a game against bots. Isn't this essentially playing offline?
    – Mana
    May 17, 2011 at 23:37
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    @Mana - custom games, even against bots, are pinging the official battle.net servers. Single player games (which can also be against bots) shouldn't ping the bnet servers, (and indeed, can be played offline) but don't count for achievements. May 17, 2011 at 23:52
  • Addition to point 3, that separate computer should be on the same network.
    – Sorean
    May 17, 2011 at 23:58

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