Has browsing some sites seem to get slow or seem slower when in Vista? Internet Explorer crashing when you go to certain sites? It may not be your imagination. Vista has a feature called ‘receive window auto tuning’ that is supposed to help optimize how Vista gets data from the network. Unfortunately, it does not seem to be compatible with many network cards, routers or even some web sites. In some cases, it can crash. Fortunately, it is easily disabled.
The easiest way to turn off auto-tuning is to open a command prompt as an Administrator (to do so, type "cmd" into the Start box, right-click on the command prompt and select "Run as Administrator”), then enter the following line:
netsh interface tcp set global autotuning=disabled
Turning it off should not have any adverse consequences. You can turn it back on with:
netsh interface tcp set global autotuning=normal
To read more about this, go here.