# Windows 7 Migration Time

A “clean install” for Windows 7 is preferred, but Windows Vista users have an option to upgrade the existing system to Windows 7.

Time estimates from Chris Hernandez, a Microsoft Software Engineer, are:  
![](//i37.tinypic.com/2zyle9u.png)

.  
from,

- **[Microsoft: Windows 7 upgrade can take nearly a day](http://arstechnica.com/microsoft/news/2009/09/microsoft-upgrade-to-windows-7-can-take-up-to-a-day.ars)**
- **[Chris Hernandez’s Blog](http://blogs.technet.com/chris_hernandez/archive/2009/09/02/windows-7-upgrade-performance.aspx)**