Despite using only a GTX 280, the Phenom II was only a few FPS behind the 8350 at all times gaming wise. It is also running Windows Vista. I'm running Windows 8. Other than processes that don't rely on OS, GPU, RAM, or HDD speed it's an unfair comparison.
Yeah, it's definitely not a perfect side by side comparison, but it gives you enough information to make a relatively informed decision.
It's a hell of a lot better than searching for hours for what is a perfect side by side comparison for every single bench that you're interested in, though, lol. One site will have one bench that you want, another will have another, and so on, and so on, etc.. Anandtech just makes it easier and it's good enough.
Edit: The gaming benches are always the ones that are a bit off between generations of CPU's with Anandtech. Everything else is usually spot on, though.