We've just started rolling out Windows 7 to our desktops and have started getting complaints from some users about slow network file access when using some bespoke internal software. We've slapped WireShark and FileMon on the system in question and started interrogating the logs. We can see that the bespoke software is accessing its data files by reading 48 byte records one at a time from a flat binary file. When this file is on the network we see in WireShark that Windows XP requests the file in 4096 byte blocks with packets split by MTU, and serving the file access requests from the cached copy. By contrast, Windows 7 is actually transmitting a request to the file server for every 48 bytes, increasing the traffic considerably. I have a feeling that this is what's causing the file access slow down as the final network traffic for the 4096 bytes requested is 4438 bytes (inc. Request & Response at the Ethernet level), whereas the final network traffic for the 48 bytes requested is 282 bytes (also inc. Request & Response at the Ethernet level). This means there is only an 8% overhead with XP's traffic, but a 487% overhead on Win7's. Obviously, the best way to resolve this is to change the bespoke software to slurp the whole file up, or at least grab it in 4096 byte blocks, and deal with the sub-reads internally, but that will take time to implement and test properly. Does anyone know of a way to make Windows 7 act like XP in this regard as a stop-gap measure until we fix the bespoke software? If this is a red herring and I'm going of on the wrong track then please feel free to correct me also. Kind Regards, Mike Coats

Hi Mike Coats, Thanks for posting in TechNet forum. The SMB is difference between Windows XP and Windows 7 to access a server. SMB 2.0 was introduced in Windows Vista and Windows Server 2008. SMB 2.0 is designed for the needs of the next generation of file servers. If you have Windows 7 and Windows 2008 server, the new SMB file system protocol could give you a faster job. In your situation, you access a Linux box, if it understands SMB 2.0, SMB 2.0 is used for communication. Otherwise, it uses SMB 1.0. Therefore, I suggest you use SMB 1.0 as expected. Follow the "Resolution" section in this KB: http://support.microsoft.com/kb/281308 , Modify the registry in your Windows 7 client, please backup the key before the modification. Then check if it will speed up like Windows XP. I would like to share this blog with you: What's new in SMB in Windows Vista http://blogs.msdn.com/b/chkdsk/archive/2006/03/10/548787.aspx Regards, Miya TechNet Subscriber Support in forum. If you have any feedback on our support, please contact tngfb@microsoft.com This posting is provided "AS IS" with no warranties, and confers no rights. | 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.

Hi, What's going on? Please feel free to give us any update. Regards, Miya TechNet Subscriber Support in forum. If you have any feedback on our support, please contact tngfb@microsoft.comThis posting is provided "AS IS" with no warranties, and confers no rights. | 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.

As this thread has been quiet for a while, we assume that the issue has been resolved. At this time, we will mark it as 'Answered' as the previous steps should be helpful for many similar scenarios. If the issue still persists, please feel free to reply this post directly so we will be notified to follow it up. Thanks for your understanding and efforts. Regards, Miya TechNet Subscriber Support in forum. If you have any feedback on our support, please contact tnmff@microsoft.comThis posting is provided "AS IS" with no warranties, and confers no rights. | 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.