May 182009

You may experience poor file copy performance over the network in Windows 7 PCs. This could be caused by the Wndows “Remote Differential Compression” engine. Remote Differential Compression is a Windows feature introduced in Windows Server 2003 and is available on all later versions of Windows. This Windows feature is enabled by default in Windows 7.

Remote Differential Compression (RDC) allows data to be synchronized with a remote source using compression techniques to minimize the amount of data sent across the network. RDC is different from patching-oriented differencing mechanisms, such as Binary Delta Compression (BDC), that are designed to operate only on known versions of a single file. BDC requires the server to have copies of all versions of the file, and differences between each pair of versions are precomputed so that they can be distributed efficiently from a server to multiple clients.

There seems to be a problem with this Windows 7 and disabling this feature resolves the problem with slow file copy performance.

To disable Remote Differential Compression,

1. Click Start – Control Panel – Programs – Trun Windows features on or off


2. Uncheck “Remote Differential Compression” and click OK.

3. Restart the computer and you should see an improved performance with copying files.

If there is a similar problem in your Windows Vista PC, you may try this and check if this helps.

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  41 Responses to “Slow Network File Copy issues in Windows 7 caused by Remote Differential Compression”

  1. Your post is inaccurate.

    RDC feature is purely a DLL install, and is not used by any Windows components.

    See the post below from Microsoft clarifying this.

    Any change seen after diabling this feature are either imaginary, or caused by the reboot / changed network conditions.

  2. I beg to differ I followed the steps listed and I went from 2.5 to almost 6mb after restart, it worked, eternally grateful!

  3. The problem in most cases will be the scalable network pack in conjunction with certain network adapters, especially Broadcom 57xx chips.

  4. I beg to differ with your beg to differ. I concur with fsexpert.

    I followed the steps. Did not reboot or restart (how ever the OS might have stopped and started service as part of the change) but it resulted in an immediate improvement from KB/Sec back to mb/s in ranges of 3x to 5x on differenct tests. And I can repeat the scenario.

    Whatever the underlying reasons are doing this change is a catalyst to the end result of performance increase.

  5. Make that I concur with Bryan

  6. I have a Broadcom 400x 10/100 NIC and after disabling, without a reboot, I saw immediate and substantial improvements. thanks much for this posting.

  7. Just SUPER from 1,5% inuse to 50% inuse(after reboot), thx

  8. I agree with Brian to.

    I tried to copy a 1.5GB file over to my Windows 7 system and it said the file copy would take 3 and a half hours!(I can actually download it off the Internet faster than that)

    I then tried your step of unchecking RDC.

    The same 1.5GB file now says it will take 7 hours!!!

    Microsoft started off being shit and over the decades everything they do just gets more and more crap.

    In another 10 years we won’t need to buy a new operating system, all we’ll need to do is shit on a hard disk to get the same result.

    The best way to optimise Windows is to disable every feature, every security patch and every program written by a Microsoft programmer.

    Inside every Windows computer is a geriatric old man with altzimers a pencil and a piece of paper.

  9. Thanks for the info. It really increase the speed trafic between windows vista and windows 7 computers.

  10. To be honest, i do not know what happened to your system but without rebooting i didn’t see any difference :P

    Installing something so i will reboot later.

    I do really wonder what happened between the beta and full release though. I only have networking problems in the full version… (wth microsux…) And in the beta, coppying went much and much faster! MS TEST BEFORE ENABLING!!!!

    Btw, Sci-Fi Si, i do agree with you, but erm… your windows must run pretty good to see it will take 10 years before your windows pc runs as bad as crapping on your harddisk… i’d say we already are that far right now :P

  11. I just upgraded to 22Mbps thru Comcast and was getting almost that on my xp laptop but not on my Win7 desktop. I could get about 10Mbs after a reboot but moents later it would slow to around 4Mbps and remain. I made the change above and I am getting over 17Mbps on the speedtests consistently, even while watching streaming videos and downloading large files. I’d say the fix works. Thanks! I was getting pretty frustrated as I am paying good money for the speed and as my laptop was getting it I sure couldn’t complain to Comcast. It was clearly not a problem with the bandwidth they were providing me. Thanks again!

  12. I have two almost identical laptops side by side. One with Vista and one with Windows 7. Vista pushes 10Mbps and 7 averages 1 to 2. This fix did nothing but waste my time. I did everything it said plus disabled and then re-enabled my network adapter and got no increase at all.

  13. Go to command prompt and type:
    netsh int tcp set global autotuninglevel=disabled
    then hit enter. (you have to do it as an admin, lol)

    No clue what it does but it sent my speeds from .91 mbps down and .95 up back to 10.84 mbps down and 11.14 up.

  14. Storm’s solution is correct. That’s what MS tech support suggested and it worked.

  15. Holy sh!t!

    I just tried this as I was experiencing an extremely slow Gigabit connection. It went from 300kB/s to 40MB/s!!!

    Thanks heaps!

  16. I’ve been trying all of the “solutions” for two years on vista and now windows 7 and nothing works. I have 2 laptops that are slow and a desktop with ethernet on motherboard and additional ethernet card and the desktop is slow with either one disabled.

    I run a VM with XP on the machines and copy from shared directories on that machine to the network machine. Copies that take OVER 3 HOURS from vista or windows 7 take UNDER 1 MINUTE from the XP VM. It’s using the same hard drive, same network card, etc, and copying the same files and it’s over 180x faster in the XP VM. It happens with 1 large file or multiple little files.

  17. Hey,, Guys ! Im on a 4mbps line.. after a fresh install of windows 7 , i was able to watch streaming HD videos and tec… the download speed was 3.6 MBPS … but after installing firefox and latest drivers.. my browsing speed was crap.. it look about 22 seconds to load up google :(

    what i did was typing this on cmd , netsh int tcp set global autotuninglevel=disabled

    as admininstrator,, it really worked well ;) , , i must mention this too , after using the method posted in this blog,, my download speed is now 3.9 mbps pe seonds,, how coool is that,. ?

    for those who talk crap about this method over here , why dont you create a solution then ?

    This increased my filecopy speed as well . from 3.2 to 8.5,
    Winsockfix contributed something to us,.. but all those guys who talks crap about this method .. give us a cool method instead :D

  18. I disabled RDC and saw an immediate improvement. Before, copying a 2 GB file hung my system requiring a reboot. After the change, the transfer only took 6 minutes on a gigabit network.

    Thank you! I have been looking for a solution to this problem for over a month.

  19. I’ve been struggling with painfully slow file transfer speeds since upgrading to Win7 back in February. This is absolutely brutal…..over a wireless N network I’m getting speeds of 235 KB/s. Using the exact same router and NIC on my WinXP machines I was getting significantly faster speeds….about 2.5 MBit/s.

    Takes over an hour to move a 905 mb file.

    Tried deactivating remote differential compression, and it did nothing for me.

  20. I had the exact same problem;

    My system -

    Windows 7 Pro 64
    Core i7 940
    Dual 500gb SATA’s 7200rpm
    Gigabit ethernet

    Gigabit ethernet switch
    Gigabit Router

    Buffalo NAS 1TB, RAID 0, Gigabit Ethernet


    I was getting transfer speeds of a maximum of 500 / 600 Kb/s between local hard disk and network storage disk. I went through a number of *fixes* on the web without any success, however I disabled ‘TCP AutoTuning’ and ‘RSS’ rebooted and voila I now get transfer speeds of 9 – 10 Mb/s to and from the network disk.

    The fix
    It should be noted that additionally to this I have updated to the latest updates, for Windows, and turned RDC off in Windows Options under Programs/Features.

    How to Disable TCP AutoTuning and Receive Side Scaling

    Open an elevated command prompt with administrator rights.
    Type the following commands and press Enter (the second command on RSS is optional):
    netsh interface tcp set global autotuninglevel=disabled
    netsh interface tcp set global rss=disabled

    Reboot computer.

    website design agency wirral

  21. I’ve tried all these tweaks, enabling and disabling or services. None of them work. Using Win7 x64 Ultimate
    54Mbps WiFi. Transfering to another Win7 x64 Ultimate is painfully slow.

    I expect at most 6.75MB/s as that is the theoretical maximum for a 54Mb/s WiFi connection but i only get around 300-400KB/s

    My connection strength is on full. Surfing the internet is perfect but networking on WLAN is horrendous.

  22. Maybe Windows 7 is just another P.O.S! I wish someone would kick Bill Gates in the balls.

  23. Are you master sure that they exists?

    Setting only
    netsh interface tcp set global autotuninglevel=disabled
    fixed my Optiplex 780 with Intel 82567LM NIC.

    At home I have HP dual port Gigabit adapter but not having problems with the network speed.

    To me this sounds like an driver issue.


  24. man your guys computers must suck. When I copy/move files on my computer I generally average 23-32 MB/s transfer speed. However going over my network to a diff PC It decreases all the way to 1 mb/s. I am about to reboot now and see if this works…

    Thanks for the tip.

  25. EDIT: just restarted. There was about a 400-500 kb/s increase. went from 750-800 kb/s to 1.3 mb/s

    Insignificant, who knows maybe its going faster b/c I restarted my pc for the first time in a couple weeks. 24x slower than my regular copying speeds = so dumb

  26. I just followed Matt’s instructions and had success! Thanks a bunch. I was experiencing slow transfers, starting off at a decent speed but very quickly diminishing and even disconnecting. Thanks to these tips I have my regular pre-Win7 transfer speeds back.

  27. Thank you sooo much. This is the one thing that has bugged me about windows 7. Now everything copies from win7 to xp as fast as from my xp machine to win7. Got sick of having to copy things using my xp machine. RDC disabling for the win.

  28. Interesting problem. We are experiencing the problem in reverse. Copying from Windows server 2008 to a Windows 7 machine is fast. Copying from a Server 2008 (Gb NIC)through a 100/10 Switch to a XP machine with a 100/10 NIC is really slow. Close to 10Mb/sec speed instead of 100Mb/sec. We know its something to do with the Server 2008 OS or the NIC settings on it.

    Any thoughts?

  29. The proof is in the pudding and this change has for certain increased the throughput in copying files from one Win7 PC to another Win7 PC. I copied 8GB of data from one machine to the other and it took 3 hours. I then deleted the files, made the changes on both PCs, and rebooted both machines. I copied the same files again and the copy only took an hour. While copying the files the first time the network utilization was around 17% and with this change the utilization has increased to +40%. I don’t care what MS says because what MS does is different.

  30. Win7 will not copy large files to a WinXP computer on a home network… my solution is

    Open a command prompt and use the old DOS copy command, as…

    copy C:\ThisDir\MyFile.avi \\NetVol\ThatDir

    At the end, you should see the “file copied” message

    Of course, things you enter/change

    C: will be your drive letter
    \ThisDir\ will be your origin directory name
    MyFile.avi will the your file name

    \\NetVol\ will be your network volume name
    \ThatDir will be your target shared/mapped directory

    I have done this with several files, largest is a 3.5Gig video file, going from Win7 64bit Pro to WinXp

    I have no idea why the old DOS copy command in a command prompt window works where Win7′s Windows Explorer does not… but this has solved the problem for me

  31. Definately helped me! I have been having issues over gigabit between win7 x64 on my main gaming rig and between my media center pc which is also running win7 x64. Was doing my head in! Since I made this change 5 minutes ago I am now getting speeds of 100mb/s + over gigabit. Cheers for the fix! Happy Times!

  32. This didn’t work for me. Still getting errors. File copies from XP Pro SP3 to Win 7 start quickly then stall. XP errors out with Cannot copy “FilenameX”: The specified network name is no longer available.

    Win7 to XP Errors after asking for my password. Turning password off in Win7 still asks me for my password.

  33. I just disabled this on both my Win 7 machines.

    I was transfering my data from one win 7 machine to a new one, as the old one I am giving to my kids.

    I was copying over at 148Kbps prior, it is now going at 10.1MB/second.

    It is also now displaying an Estimated time remaining of 3 hours for 106GB of Data.

    The little green bar has moved further in the last 5 mins, than the hour I had it transferring at the low rate. So vast improvement for me.

    I also have both network adapters set to autonegotiate.

  34. Just for an update on this. I just got done transferring 3gb worht of files from a Windows Home Server box on a 1gigabit wired network . Before this change, I was hitting right around 6.45MB/second with the transfers completing in around 10 minutes. After making the change on my Win7 box, I immediately shot up to an average of 78MB/second and the transfers got done in just under 60 seconds. Don’t care if it’s voodoo or what, but this was exactly the fix I needed.

  35. In a mixed environment (copying from Win7 to XP) the tip solved all my problems, copying is now lightning fast again, no more minutes waiting before being forced to terminate the explorer process!

    Thanks a lot, it was giving me real headaches!

  36. It works great for me. Copying speed goes up by at least 100% of previous speed(before unchecking compression).
    Awesome post!!!!!.

  37. Background intelligent transfer service was my problem.

    Changed to Manual/Stopped.
    Win 7 slow, moving and copying files, all fixed.

  38. Worked fine for me, thanks!

    Was copying files thru gigabit lan and the speed before the change was 7mb/s.. with this disabled, around 30-40mb/s… BIG difference!

  39. I fix the problem by type in cmd:

    netsh int tcp set global autotuninglevel=disabled

    now work fine.

  40. I noticed that I had one PC that moved files at about 20KB/s when moving to whs 2011. Coming from whs 2011 it was near instantaneous (couldn’t get explorer to show me a rate).

    I tried this same PC to/from another PC on the network (same switch and same with whs 2011) and it was nearly instantaneous each way. Tried from another PC to/from whs 2011. Instantaneous.

    Found this post and turned off RDC. Transfer both ways now instantaneous. RDC IS turned on on the other PCs but they have a slightly newer NIC driver (PCI GBE Family 7.46 vs 7.43). Update my NIC to latest (7.58), turn RDC back on, reboot. Instantaneous.

    I do wonder if I had done nothing more than turn RDC off, reboot, turn RDC on, reboot if that might have also remedied the situation but I didn’t test that. Just happy it is now zipping along again (seemed to have started after I upgraded to whs 2011).

    Many thanks.


  41. It worked perfectly!

    I had this problem for a long time. File copy over network would get stuck with no reason regardless of size. I wasted hours discarding what could be the cause but to no avail. I had to use pen drives to transfer files across my PCs even when they were connected together, could see each other’s files, and play LAN games.

    Now I tried this solution and… it was magic! Lots of thanks, you have saved me countless more hours of trouble.

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