Many upgrades to Microsoft’s forthcoming Windows 7 will take one to three hours — a reasonable amount of time. But some upgrades could take more than 20 hours, Microsoft employee Chris Hernandez says on a company blog.
Exmple: For a Super User — a system that has 650 GB of data, 40 applications and 15 components — doing an “in-place” upgrade from Vista to Windows 7 could take 8 to 20 hours, depending on hardware quality. (An in-place upgrade to Windows 7 is one that automatically retains files, settings and programs from the current Windows version.)
But that doesn’t sound like a typical experience. On less complex setups, in-place upgrades will take a more reasonable one to three hours.
Recall that many users won’t get to experience the convenience of an “in-place” upgrade at all, according to another chart produced by Microsoft. Instead, they will go through a “custom” or “clean” install, where the new Windows version will overwrite the old one.
For those, installation should be much shorter. According to Hernandez’s report, clean install should take 30 to 50 minutes, depending on the user’s system configuration. But it will take extra time before and after the installation, as users will want to manually back up data, change settings on their new Windows, etc.