In this blogpost I will describe how to reduce the WinSxS folder in the Windows folder after installing SP1. All superseded files are removed. And you cannot uninstall SP1 anymore. To know what the WinSxS folder is, read this blogpost of Joseph Conway.
First off all, how big is my WinSxS folder? Right click on it says around 9GB.
But it contains hardlinks, so how big is it for real?? Download ctTrueSize. Run: ctts C:\Windows\WinSxS
9,35GB – 1,04GB = 8,30GB