When you are using the “Open with Windows Explorer” option in SharePoint 2010 and you experience a slow performance, you can use
the following procedure to fix this and increase the performance:

1. Open Internet Explorer
2. Go to the Menu Tools > Internet Options then go to the Connections tab
3. Click on button LAN Settings
4. Uncheck the box Automatically detect settings
5. Close and restart all running Internet Explorer processes
6. Restart the Web Client Service, if needed.
7. Try it again!