Windows 7 upgraders: Set aside your weekend

Looking forward to Windows 7's October release? If you're planning on upgrading your system yourself (rather than buying a new computer), you might go ahead now and block out some time. According to time trials performed by a Microsoft engineer working on the Windows 7 project, upgrades could take as long as 20 hours if you're a serious power user.

Chris Hernandez benchmarked the time it took to complete an upgrade from Windows Vista SP1 to Windows 7 under several scenarios: A "clean" upgrade with no data or applications ported over, a "medium" scenario with 70GB of data and 20 applications reinstalled, a "heavy" case with 125GB of data and 40 applications, and a "super" scenario with 650GB of data and 40 applications copied to the new OS. He also used three different types of hardware (low-end, medium, and powerful), and did each test with both 32-bit and 64-bit operating systems.

The results are surprising. If you don't have much on your machine, you're in luck no matter what your hardware looks like. Even with low-end hardware, the "clean" case gets you upgraded from Vista to Win 7 in less than an hour. But as the apps ramp up and the amount of data explodes into the hundreds of gigabytes, watch out: You can be facing hours of time copying data from a backup hard drive and reinstalling applications from scratch. In the worst case tested (a 32-bit "super" user case on mid-range hardware), the total time spent on the upgrade was more than 20 hours.

Most of us don't have that much data, fortunately, but based on Hernandez's numbers I'd expect that three hours, minimum, is likely to be required for anyone doing the upgrade themselves and who uses their PC in relatively common fashion.

Hernandez is quick to note that this is actually an improvement over Vista's upgrade process: Reinstalling Vista SP1 over an existing copy of Vista takes about 5 percent longer than doing the Windows 7 upgrade.

Also, in most cases you won't see much of a difference in using the 32-bit vs. the 64-bit version of Windows. For most cases installation times are within 15 minutes of each other (32-bit is faster on clean installs, 64-bit is faster on others). The exception is for that mega-data super user, which purportedly goes far quicker on 64-bit hardware, cutting that 20-hour install into about 11 hours of effort. Something to keep in mind if you're facing a lot of data to move from one machine to the next.

Via Ars Technica.