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Updated: 10-28-12 05:16 AM
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The Adventure Continues (6.1)
Warlords of Draenor (6.0.3)
Warlords of Draenor Pre-Patch (6.0.2)
Updated:10-28-12 05:16 AM
Created:05-23-09 01:32 PM
Categories:Leatrix Projects, WoW Tools & Utilities

Leatrix Latency Fix  Popular! (More than 5000 hits)

Version: 3.00
by: Leatrix [More]


Leatrix Latency Fix will reduce your online gaming latency significantly by increasing the frequency of TCP acknowledgements sent to the game server. For the technically minded, this is a program which will modify TCPAckFrequency.

You will see reduced latency in many online games including World of Warcraft, WildStar, Heroes of the Storm, Elder Scrolls Online, Guild Wars 2, Diablo 3, Star Wars: The Old Republic, Rift and more.

Note that Leatrix Latency Fix performs a different modification to the 'Optimise Network for Speed' setting in World of Warcraft. They are not the same thing and can be used together (more information on this in the FAQ).

System Requirements

  • Windows 7, 8, 10, Vista (SP1+) or XP (SP3).
  • Both 32-bit and 64-bit versions of Windows are supported.
Macintosh users should read the guide here.

Installation Instructions

You can watch a short installation video here.

Simply download the zip file, extract it and then run Leatrix_Latency_Fix_3.00.exe. When the program launches, click the Install button. You will see the status change from 'Not Installed' to 'Installed'. You need to restart your computer (or disable/enable your network card) for the changes to take effect.

Your Windows account needs to have Administrator rights in order to install or remove Leatrix Latency Fix. If your Windows account doesn't have Administrator rights, you will be prompted for the credentials of an account that does have them.

After Leatrix Latency Fix has been installed, you can login to your online games with reduced latency!

To uninstall Leatrix Latency Fix, click the remove button and restart your computer.

For reference, the status line in the program will show 3 possible tags. 'Installed' indicates that all network interfaces have been modified for reduced latency. 'Not Installed' indicates that no network interfaces are modified for reduced latency. 'Partially Installed' indicates that some network interfaces have been modified for reduced latency. You will see this status tag if you add a new network card (or perhaps a USB modem) after the installation of Leatrix Latency Fix.

Errors and Unexpected Behaviour

If you have any problems with the program, please click here to send me a message. Include your operating system and service pack as well as any relevant information (such as error messages). You can also try version 2 if you prefer (available here). Version 2 requires the Framework (available here) but the mechanics are identical to version 3. You can watch a short installation video for version 2 here.

If you are having problems downloading from Wowinterface, please use this link on Dropbox (this link is subject to change so please don't share it elsewhere).

More Information

There is a FAQ covering pretty much everything here and there is a short installation video tutorial here.

To ensure that people always use the genuine Leatrix Latency Fix program, please don't publish it elsewhere. It's completely free so there is no need to. Please link to instead.


Some official and unofficial videos and websites referencing Leatrix Latency Fix are listed below. If you have made an honest webpage or video featuring Leatrix Latency Fix and you would like to see it listed here, just send me a private message.

Official Leatrix Sites
Unofficial videos featuring Leatrix Latency FixLinks, fansites, nice people and interesting thingsMore

Visit for genuine Leatrix software.

Leatrix software is protected by copyright and is hosted ONLY on and Stay safe online and download only from genuine Leatrix sites.

  • Leatrix Latency Fix 3.x is written in Python.
  • The Python configuration files are bundled with the download.
  • Integrated Microsoft User Account Control and Administrator rights detection.
  • This update is recommended for new users but optional for existing users.
  • Updated exception handling.
  • Simplified the code structure.
  • Restarts are no longer done for you so that you can choose whether to restart your computer or network card.
  • Leatrix Latency Fix 2.x is written in Visual Basic (Microsoft .Net Framework 4 required to run).
  • Updated the restart process.
  • To avoid confusion, unknown interfaces will no longer be listed in the checker script.
  • The checker script will now show network interface names and identify virtual or DHCP addresses correctly.
  • The checker script will now show IP addresses for the network interfaces which have been modified.
  • You can now run Leatrix Latency Fix from batch files using 'cscript <script name.vbs>' (eg. 'cscript c:\install.vbs'). Administrator rights are required for this.
  • Added a checker script which will inform you whether Leatrix Latency Fix is installed or not.
  • Added support for Microsoft's User Account Control.
  • First release.
Archived Files (1)
File Name
10-22-12 12:51 PM

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Unread 03-26-10, 03:07 PM  
A Kobold Labourer

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Awsome Fix, works a charm

Windows 7 Professional X64
Before: 250 - 300ms
After: 18 - 30ms
Line Type: 24/3mb SDSL
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Unread 04-10-10, 01:22 AM  
A Kobold Labourer

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Leatrix thank you for this great addon, deep respect man, my latency before using this addon was 165ms-250ms, now its 72ms-98ms, thank you again ill never forget!
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Unread 04-10-10, 06:18 AM  
A Kobold Labourer

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Re: Latenfy Fix Results

600-700 before
200-300 after
win 7
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Unread 04-11-10, 05:08 AM  
A Kobold Labourer

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Thank you for creating this great script here is the results;
200-300 before
90-100 after
on windows 7.

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Unread 04-12-10, 12:13 PM  
A Cyclonian
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I had around 300ms before LLF and it dropped below 100ms after installing it.
Used to be (1y4m ago) below 100ms all the time but now there are three computers instead of one connected to the same router. (a bit offtopic, yes)
Oh and.. Win 7 64bit
Last edited by flaicher : 04-12-10 at 12:14 PM.
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Unread 04-16-10, 02:39 PM  
Every day I'm shuffling
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WoWInterface Admin

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I would just like to confirm WoWI has tested this file extensively and it is safe.

The files are vbs so you can look at the source, nothing is hidden. 40 other virus scanners confirm that this is safe: All files uploaded to WoWInterface are manually checked and executable files are held to even a higher standard and are pulled apart in a sandbox before made available to download.
Last edited by Dolby : 04-16-10 at 03:06 PM.
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Unread 04-16-10, 05:15 PM  
WoWInterface Super Moderator
AddOn Author - Click to view AddOns

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Aside from what Dolby has already said, this download isn't even compiled. All of the source code is available to anyone that wishes to view it; they're VB scripts. I encourage anyone that knows what they're looking at to review them. You should find nothing out of the ordinary.
It's my turn next.

Shakespeare liked regexes too!
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Unread 04-20-10, 07:29 PM  
A Defias Bandit
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Love you
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Unread 04-25-10, 08:05 PM  
A Murloc Raider

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Gotta agree with the poster below
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Unread 09-22-13, 10:16 AM  
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Arrow Leatrix Latency Fix

Leatrix Latency Fix is actively developed and maintained. The comments section here on Wowinterface is closed so that queries can be dealt with courteously and professionally on an individual basis.

I hope you enjoy using Leatrix Latency Fix. If you wish to report an issue, please send me a message. All reports are investigated and replied to.

In order to keep Leatrix Latency Fix up-to-date, make a free Wowinterface account, enable the email notification option and favorite Leatix Latency Fix. You will be sent an email when an update is released.

Only download Leatrix software from and Files hosted anywhere else are not genuine.
Last edited by Leatrix : 02-21-14 at 01:56 AM.
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