I've been running various builds of Windows 7 on a number of systems here at the lab since December of last year. Over time, Windows 7 became my default OS on several systems that are in daily use. During that time I've captured a lot of real-world reliability data for the OS.
I'm going to be concentrating on data gathered from three heavily used Windows 7 systems. I'm going to focus on Windows 7 reliability data only for the RC (Release Candidate) and RTM (Release to Manufacturing) releases of the OS. I have data going back much further than that, but it's the final release that people are most interested in.
So, how reliable is Windows 7?
In a word, very. Even thinking back to the earliest pre-beta builds that I tried, I have always been impressed by the stability of this OS. Not only have I considered Windows 7 betas to be more stable than previous OS betas from Microsoft, they were at least as stable as Windows XP and Vista. That's very unusual for beta OS builds (heck, that's unusual for the RTM code too ...). It was obvious to me early on that Microsoft had put reliability right at the top of the list from the beginning.
Since I installed the Windows 7 RC build, and later the RTM build, the OS itself has performed almost flawlessly. In fact, after thousands of hours of usage over several systems, I've had a handful of shutdown issues (which I have fixed by updating drivers) and some problems with a few applications, in particular the third-party PDF reader Foxit. These have been harder to fix but as we edge closer to the release of Windows 7 (due October 22nd) software compatibility is getting better.
Below is a screen grab from the Windows 7 reliability Monitor on my Dell Studio XPS 13 notebook:
If I took Foxit out f the equation here, we are looking at a small number of shutdown issues having a small impact on reliability, a pattern that I see on all my Windows 7 systems. Windows 7 seems rock solid, and as drivers and applications become more mature (and they're doing so daily), reliability will improve.
Bottom line: Windows 7 is a solid, robust OS.