Local Area Network : How to fix slow LAN transfer speed of files in Windows 7

Recently I had to solve a problem of a very slow transfer of files between two computers on a LAN network using Ethernet cable. Both machines had Windows 7 x64 installed and the transfer speed was ridiculously slow at 10-15kb/s. Using Task Manager under Networking tab, Network Utilization was showing only around 0.25% for Local Area Connection.

I looked around the web for solutions and found quite a few suggestions how to tackle this problem. Those that I tried and the one that finally solved my problem are discussed here.

windows-7-features

Turning off “Remote Differential Compression”

One of the first suggestions that I came across was to turn off this Windows Feature in Windows 7.

This suggestion is common on the web but it turns out to be just a myth.

From TechNet:

This is 100% false. Neither Windows Update or file copy operations use RDC at all. 

So I ignored this suggestion and continued looking.

command-prompt-running-as-administrator-netsh

Disabling “TCP Auto-Tuning”

This is another common suggestion that I came across and it uses NETSH command-line utility used for displaying and modifying the network configuration. To make the necessary changes, we need to run that utility as an Administrator.

  1. Open Command Prompt as Administrator:
    • Click on Start Menu
    • Type Command in search box
    • Command Prompt will show up in results. Right-click on it to open Context Menu
    • Select Run as administrator
    • If User Account Control Window shows up asking if you want to allow the following program to make changes, select Yes
  2. Type: netsh interface tcp set global autotuning=disabled
  3. Restart the computer
  4. To verify that the auto-tuning is still disabled type in Command Prompt:
    netsh interface tcp show global

This suggestion still didn’t solve my problem, so I looked further but before doing that I wanted to set Auto-tuning back to the default value by typing this in the Command Prompt (running as an Administrator):

netsh interface tcp set global autotuning=normal
windows-7-network-adapter-advanced-tab

Disabling “Large Send Offload (LSO)”

Large Send Offload is a technique of improving network performance while at the same time reducing CPU overhead. Apparently it does not work very well, so it was suggested to disable it. If you would like to know about LSO, check this MSDN article from 2001.

LSO is an option located in a Device Manager under your network adapter, so this solution requires Administrator Privileges.

Follow these steps:

  1. Open Start Menu, right-click on Computer and select Properties
  2. Under Control Panel Home located on the left side of the window click on Device Manager
  3. You will get a list of all devices on your machine. Expand Network Adapters.
  4. Find your Network Card and double-click on it.
  5. Select Advanced tab. You will get a list filled with different options.
  6. Select Large Send Offload V2 (IPv4) and set the value to Disabled
  7. Do the same for Large Send Offload V2 (IPv6) if it is available
  8. Click OK

After clicking OK, I tried to send a file over the LAN network. The transfer speed started very slow, but it was gradually picking up speed. I decided to restart the computer and try to send that file again and this time it worked like a charm.

Now that sending of files worked as it should, I also checked speed for receiving files. It turned out that it was still slow but all I had to do to fix that was to disable Large Send Offload V2 on the other computer. Once done,  the problem was solved for receiving files as well.

Conclusion

In this post we examined different ways to solve slow speed on a LAN network. One of them is just a common myth, but for other two you need to have administrator privileges. I hope you found this article useful. Consider sharing it on a social networks. Comments are also welcome.

If you solved your slow LAN speed problem in a different way, let me know how and I might add that solution to the list.

46 thoughts on “Local Area Network : How to fix slow LAN transfer speed of files in Windows 7

  1. Thanks a lot for that !!!
    After months enduring a terribly slow transfer between two win7 computers, after having reinstalled the OS, turn off all firewalls, all anti-virus and even reinstalled all LAN card drivers, I could not solve this issue. Transfering a 500K file could take up to 15 minutes !!!
    After disabling the LSO on both computers (no need for reboot), the transfert took less than 1 second.
    Thanks for this and shame on M$ engineers ;-)

    • Hey Brother, i am also facing same problem my transfer speed is about 1-1.5MB/sec……i just want 2 ask u that disableing ipv4 & 6 is enough?? To increase transfer speed……….

      • Actually this worked for windows 8 too with speeds @1mb/s. At first i got around 20-30mb/s, then dropped @1mb/s, and now after disabling LSO, finally works @85mb/s.
        Thanks!!

  2. Mate, it worked like a charm for me also without a restart so thank you very much. Just makes me wonder why this setting has caused me this problem when it never has before? Oh well, it’s working now and I don’t have time to ponder that.

  3. hey, I woud like to thank you, but it not solve my problem. Do you have any other idea? I have 2 pc with win 7 home. The lan speed of connetcion is below 2 Mb/s.

  4. Try booting from “Safe Mode with Networking” to see if some third party software is not the cause of the problem.

    Another possibility could be a defective cable.

  5. I went to the advanced tab as mentioned above, and I have “Jumbo Packet”, which I assume is the same thing as LSO. But it is set to ‘disabled’ already. What else could be the problem here? We have a mix of xp and 7, with our server being 2003 SP2

  6. Thank you! Your last suggestion worked in the midst of a Windows Easy Transfer. Network utilization was less than 1percent on two Windows 7 64-bit machines. After, it jumped past 60 percent and stayed there on both machines. Thank you so much for sharing this info.

  7. Finally!!!! I have been battling this for along time. My problem was RDP and file playback from a Win 7 64bit to a Win 7 32bit. Before the fix it was so trying do either it was not an option disabling “Large Send Offload” worked for me. Thank You Thank You

  8. You just made my day! Thanks so much. After stuffing around for nearly a full day without success I finally landed on this site and B I N G O !!! I still do not know what caused the problem but it appeared immediately after installing a new Internet Security Software on all Workstations. Thank you again.

  9. This worked wonders. I had my Pictures folder (40 GB) that I needed to transfer to the new 3 TB drive located on another networked computer. It at first said 19 hours, but after this fix it’s down to 8 hours. I still think that’s too slow, but it dropped to half so thanks for that.

  10. God! it’s awesome thank you! till now i was like using an usb drive to move file between my comps now i can copy! i can COPY, my speed was like 5k and now it’s 5mb! thank you !

  11. Had the same problem. My network server is XP machine. My new (used) laptop is Win7.
    The “Jumbo Packet” setting did not solve the problem. I solved it by changing the “speed/duplex” setting in the advanced tab of the XP server’s network card properties to “Full Autonegotiation”. It had been set on “Force 100″ My speed went from about 150kB to 10Mbyte.

  12. First i realy want to thank you for this.still,i don’t understand why the speed is about 2 to 3 mb/sec when sending a large movie file…

  13. Man I have had this issue for a long time. I thought that I have tried everything to pickup my LAN file transfer speed and nothing worked. Till now. I disabled LSO and WOW! Even large files transfer in seconds. Thank you very much for sharing this info.

  14. I’m sorry, I’ve tried all the solutions, unfortunately, my problem continues ..
    Win 7 to XP Copy fast
    XP to win7 fast,
    but slow from win7 to win7 .. 100-300 kbsn 1,50 gb Total = 5 hour

  15. I also had 1 MB LAN transfer speed and found one thing that helped !

    Try disabling IPv6 – now it’s around 80 MB per sec.

    system on both computers – WIN 7

  16. I have 3 PCs. PC1 is our server PC with a practice management program. I have mapped the drivers of the 2 workstation PCs to the server PC for full access of the program (read and write). I have turned off LSO and network speed has improved but only when one workstation is on at a time, when both workstations are on, network speed is slow. Does anyone know what else could be the issue? Have I mapped the drivers wrong? Do I need to reset my modem?

  17. Wow, changed settings in the middle of a copying files. Estimated time started at over a day and dropped to mater of about 20 minutes.

    Thanks!

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