• Carrot: Improve latency in WoW (On Windows)

    Characters: Glorif[85] Heclan[73] Nathrezim[37] Cuchillo[23]
    Created: 2009-09-19 00:51:03 Edited: 2010-02-16 10:07:56

    Was linked to this from another forum I frequent, and I was initially dubious. However it all seems to check out, and the way it works makes sense. I had wondered for a while how Chris could have 50ms latency when Andy was in the same house on the same connection and getting >100. This fix, which is actually some Windows registry hacks instead of a WoW addon, explains why and then fixes it so you get less latency in Windows too. I was getting about 120ms, installed this, and went down to 43ms:

    http://www.wowinterface.com/downloads/info13581-LeatrixLatencyFix.html

    The short version of the explanation he gives is:

    Wow uses the TCP protocol which requires that network segments sent to your computer be acknowledged in order to provide a reliable connection.

    Windows bundles these acknowledgments together and sends them in pairs. While this is an efficient way of dealing with them generally, the inevitable delays caused by the bundling process increase latency considerably.

    This is because when Windows queues up an acknowledgment in order to bundle it with the following one, the game server has to wait for the acknowledgment timer to expire before sending new data.

    Leatrix Latency Fix removes the acknowledgment bundling process so that an acknowledgment is sent immediately for every segment that's received. This produces a significant reduction in latency as there is no longer a delay before new data is sent to your computer.

    In a normal networking environment, you would prioritise network efficiency over latency and use the Windows defaults, but in Wow the opposite is true and you want the lowest latency you can possibly get.


    This will also help lessen latency on any other games that use TCP, mostly MMOs and RTSes or similar. FPSes tend to use UDP instead of TCP, which doesn't do packet acknowledgement so will be unaffected. This does, however, explain why I was consistently getting latency of about 40ms in CoD4, CS etc etc, but always around 150 in WoW.

    (Edited 16/02/2010 by Andy to sticky and to hyperlink the url)
    Wash: This is going to get pretty interesting.
    Mal: Define interesting...
    Wash: Oh god, oh god, we're all going to die?

    • Andy: Re: Improve latency in WoW (On Windows)

      Characters: Marlen[85] Egeria[81] Davarnon[80] Lyia[61] Krafla[34]
      Created: 2010-02-15 10:26:33

      Uhm, I did this when I wad running Vista and it seemed to help. Do you think I need to do this again now I'm running 7? I appear to still be getting a higher latency than Chris..
      "My interest in what you're talking about is low to moderate" -- Vork

      • Chris: Re: Re: Improve latency in WoW (On Windows)

        Characters: Allynne[85] Phelia[85] Akkyyr[74] Aerryn[46]
        Created: 2010-02-15 15:29:50

        Did we actually compare latency last night? I seem to recall you mentioning 90ms, which is what I commonly get.

        • Andy: Re: Re: Re: Improve latency in WoW (On Windows)

          Characters: Marlen[85] Egeria[81] Davarnon[80] Lyia[61] Krafla[34]
          Created: 2010-02-15 17:40:16

          No, I think I was getting 190 or something stupid
          "My interest in what you're talking about is low to moderate" -- Vork

    • Peter: Re: Improve latency in WoW (On Windows)

      Characters: Rittal[85] Mieville[80] Terlan[80] Caltera[67] Dynia[67]
      Created: 2010-02-15 11:23:38

      I did this again on Windows 7 and it appeared to help me. Are you saying you've done it Andy and it didn't make a difference?
      "I may not have gone where I intended to go, but I think I have ended up where I needed to be." -- Douglas Adams

      • Andy: Re: Re: Improve latency in WoW (On Windows)

        Characters: Marlen[85] Egeria[81] Davarnon[80] Lyia[61] Krafla[34]
        Created: 2010-02-15 12:39:13

        Nope, haven't done it in 7 yet, will do tonight though.
        "My interest in what you're talking about is low to moderate" -- Vork

    • Andy: Re: Improve latency in WoW (On Windows)

      Characters: Marlen[85] Egeria[81] Davarnon[80] Lyia[61] Krafla[34]
      Created: 2010-02-16 10:05:55 Edited: 2010-02-16 10:06:16

      I did this again last night on my Windows 7 install and it GREATLY improved my latency.

      I cannot recommend enough to anyone running WoW on a Windows machine (XP, Vista and 7 only I beleive) to apply this registry tweak as soon as possible.
      "My interest in what you're talking about is low to moderate" -- Vork

      • kimball: Re: Re: Improve latency in WoW (On Windows)

        Characters: Kedaer[85] Llabmik[84] Draklon[58] Relisiel[37]
        Created: 2010-02-16 13:06:34

        I applied the equivalent fix on my mac when I was in Scotland, and it seemed to help with the less than reliable WiFi as well, so I also recommend it

        • Carrot: Re: Re: Re: Improve latency in WoW (On Windows)

          Characters: Glorif[85] Heclan[73] Nathrezim[37] Cuchillo[23]
          Created: 2010-02-16 18:54:04 Edited: 2010-02-16 18:54:38

          Um, what 'equivalent fix'? Everything I read said this was a very Windows specific thing as OSX already sends ACKs individually instead of bundling them. So you might have found a latency improvement tweak for OSX, but it's unlikely to be equivalent. No idea what it'd do really.
          Wash: This is going to get pretty interesting.
          Mal: Define interesting...
          Wash: Oh god, oh god, we're all going to die?

        • daagaak: Re: Re: Re: Improve latency in WoW (On Windows)

          Created: 2010-02-16 18:57:59

          I've never ever ever had to apply any networking tweaks to OSX to get decent latency in WoW. Even when Lea needed to do the Win7/Vista fix to get below 100ms, I was happily sat at 70ms.

        • Sara: Re: Re: Re: Improve latency in WoW (On Windows)

          Characters: Tesandra[85] Sevelyn[82] Elveria[81] Valediren[80] Eláviel[20]
          Created: 2010-02-16 19:53:15

          Yeah same here, I don't normally have any latency issues at all on my Mac Pro. In fact the reason Andy was applying the fix was because he noticed his latency was never as good as Chris' on his iMac....
          "And then there's aggro to worry about."
          "What's 'aggro'?"
          "Well, it's complicated. But loosely translated, it means 'The Priest Dies.'"

        • kimball: Re: Re: Re: Improve latency in WoW (On Windows)

          Characters: Kedaer[85] Llabmik[84] Draklon[58] Relisiel[37]
          Created: 2010-02-17 00:39:36

          Is there a Macintosh version?
          Leatrix Latency Fix isn't supported on Macs. However, you can achieve lower latency in OSX by entering the following command in a terminal window. This will disable delayed acknowledgements until you restart your computer.

          sudo sysctl -w net.inet.tcp.delayed_ack=0

          To disable them permanently, create a text file under "/etc/" called "sysctl.conf" and copy/paste the following line then restart your computer.

          net.inet.tcp.delayed_ack=0