Microsoft KB article 929868 describes a problem which will cause you to experience very slow browsing on certain websites when using IE7 on Windows Vista, and eventually the website might even drop the data completely.
To work around this issue you might consider changing the Windows Scaling factor to 2. To change the Windows Scaling factor to 2, follow these steps:
netsh interface tcp set global autotuninglevel=highlyrestricted
This will set the autotuninglevel to “Allow the receive window to grow beyond its default value, but do so very conservatively”. To read more about the netsh command in Windows Vista please use Vista’s help and support tool. You will need to reboot in order for the setting to take effect. You can easily restore the setting back to the default by typing
netsh interface tcp set global autotuninglevel=normal
Remember to reboot in order for the setting to take effect. You can also disable autotuning with the following command:
netsh int tcp set global autotuninglevel=disable
Again, you will need to reboot in order for the setting to take effect. It seems that disabling the autotuning feature will speed up threaded network downloads, mostly used with all sorts of downloading agents and per-to-peer networking, along with great improvement with file copying on your network. BTW, it also seems that disabling the autotuning of TCP can also fix other Vista-specific issues related to slow file transfer and even Outlook 2007 – to Exchange connections. Read “Outlook 2007 is not for me, performance way too slow” for more information.
A Web site sends data very slowly or drops the data completely when you use Windows Vista Enterprise – 929868 http://support.microsoft.com/kb/929868
RFC 1323 http://www.ietf.org/rfc/rfc1323.txt
The copy process may stop responding when you try to copy files from a server on a network to a Windows Vista-based computer – 931770 http://support.microsoft.com/kb/931770
When you copy large files to or from earlier operating systems, the copy operation may be slower than expected on some Windows Vista-based computers – 932170 http://support.microsoft.com/kb/932170