Windows Update version 5 incorporates a new interface and new features.
Delta Compression - Downloaded files will incorporate delta compression which only downloads the differences between the file on your computer and the updated file. This helps make file downloads smaller in size. For example, if a file.dll is on your computer and a new file.dll is available, instead of downloading the entire new file.dll, only the changes between the new and old file.dll are downloaded.
Windows Update installations use files downloaded by Automatic Updates via Background Intelligent Transfer Service (BITS), where possible. Previous versions would re-download the files, even if they have been previously downloaded for an Automatic Updates installation.
When a reboot is pending after a Windows Update installation, Automatic Updates provides a periodic reminder.
Automatic Updates can provide installation for Update Rollup packages and Service Packs.
Install at shutdown - If an update is downloaded through automatic update, the user will be prompted to install updates when the computer is being shutdown. View Picture
Note: If running on low battery power on a notebook computer, install at shutdown will not appear.