In fact, I find it works best on a box that's never seen Windows. I prefer to keep my DOS-only box in a room that has no internet connection and no telephone, and I ensure that no Windows-contaminated media be introduced into that room.

I routinely run it on another box in another room that does have Windows on the same machine, albeit Windows98, for unrelated reasons. There are driver issues, i.e. the current-generation display driver requires strict adherence to VESA standards, so some adapters, notably the ones integrated into a couple of my Windows boxes won't work properly with it.

It runs WAY (many orders of magnitude, on the order of 4 or 5) faster under DOS 6.2x than it does under Windows. What's more, it doesn't require the latest greatest CPU and it doesn't know how to use more than 16 MB of RAM. Nevertheless, no operation, aside, say, from a print or autoroute, and perhaps some library function or other, takes long enough that you can remove your finger from the keyboard before it's done.
I use a display adapter that has a native-mode driver from OrCAD, so I don't have to worry the display or printer driver issues. What's most important is that it lacks the "mode" editing features mandated by Windows' mouse-based layered (often too many layers!) approach to the user interface. That's why it's fast and Windows is slow.

RE