I have a network consisting of a single Windows 2003 file server and a bunch of Windows XP and Windows 7 clients. One of the Windows 7 clients is having some serious performance problems when using the file server (upload, download, open, etc.). The problem seems to be limited strictly to CIFS as I can download from web pages without a problem. As a point of reference, I was able to download Adobe Reader in about a minute. It took 7 or 8 minutes to copy to the file server. I checked the performance counters on the server (disk queue, TCP retransmits, and a few others) to make sure it wasn't the server, but since the other clients don't have a problem, I doubt it's the server anyways. The software load is pretty similiar on the Windows 7 clients, so I don't think it's the McAfee antivirus. I also attempted to replace the network card with a USB adapter just to eliminate device or driver concerns. Any other ideas?

Did you try to disable Remote Differential Compression on your W7 machines?

I would try applying the Hotfix update KB982860 (SMB update). It improved out file operations greatly, especially with Office documents. Also, disable IPv6 if you're not using it and make sure you're running latest NIC drivers.

Do the computers have the same model of network adapter? If so, you may need to upgrade the network adapter driver. This issue occurs if your network devices do not work properly with Network Auto-Tuning. Please follow the steps below to disable Auto-Tuning 1. Click Start, point to All Programs, and then click Accessories. 2. Right-click Command Prompt, and then click Run as administrator. 3. In the Administrator: Command Prompt window, type the following command, and then press ENTER: netsh interface tcp set global autotuninglevel=highlyrestricted If the issue persists, try to disable Remote Differential Compression. Your network device may not support this function well. 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. In some situations this issue can be resolved if you replace the router with another one that works properly in Windows 7. You can make a test if you have another router. Arthur Xie TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com.Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Thanks for the suggestions, but none of these worked. I tried these suggestions in order (reboot and performance test between each attempt): Remote Differential Compression removal, setting tcp tuning parameters, disabled SMB signing, installing the hotfix. I already confirmed I had the latest drivers (and tried an adapter with different vendor). So far, no luck. Any other suggestions?

Hi, Please let us know the model of the problematic system. Since it is the only Windows 7 computer that has this issue, it should only be caused by the exact system. How does it work if you temporary remove the antivirus? You may try to remove the current network adapter driver since it may be corrupt because of unsuccessful updates or antivirus. After removing, please install the latest Windows 7 compatible driver. Some of these issues can also be caused by hard drive firmware or BIOS. Update the firmware if it is possible.Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.