, magicalclick wrote

@kettch: no, obviously no, because Vista runs on a new driver model which caused a lot of driver issues. And win7 used the same driver model after OEM was able to address all the issues during Vista time. I have yet to hear them doing such major change that would affect graphics or the environment that runs VS. even if the emulation is slow, as warren suggested, it is still useable, not like black screen or dead pixels or random color popping out.

And Windows 7 completely ripped out Vista's explorer data layer to replace it with a new one supporting federated data sources to populate search results, etc...

Every new OS has a lot of work done and, even if it looks similar to the previous one, I would bet more than 80% of the code goes thru some update one way or another (be that refactoring, rebuilding or optimizing).