timppu: Isn't the favored way to run games in Windows 10 now the new(?) "windowed fullscreen", which to me looks like fullscreen, without even showing window borders? It gets the same benefits as windowed mode ie. easier Alt-TABbing and handling several monitors.
While I don't play on a multi-monitor setup, I agree with your reasons. The old fullscreen mode does seem a bit finicky at times, sometimes it works fine when switching to other programs, sometimes it freezes, sometimes crashes etc., depending on the game. I don't recall if it was Deus Ex (with the GMDX mod) or Deus Ex: IW which would always crash if I tried to switch out of the game, and some game (Wasteland Classic?) even has somehow prevented one from alt-tabbing away from it.
And even if it works, there is always that small "hiccup" when the system switches back and forth from and to fullscreen mode which is not in the same resolution as your desktop. Your desktop windows get resized to the smaller resolution etc. all kinds of little annoyances.
Definitely. If you are in fullscreen, every time you switch to a different program, the game stops rendering and upon returning, it has to be restarted which causes delays and is prone to errors. Some games are literally allergic to being minimized.
I've also had many games playing much smoother/it fixed some bugs in windowed mode compared to fullscreen.
The performance loss when not running fullscreen used to be an issue in older Windows but ever since Vista, it has been from negligible to non-existent. The added convenience far outweighs it with the instant alt-tabbing and not having to constantly wait for the game to restart the renderer/engine every time you go back to it.
The only bad thing is that older games don't usually have the borderless window option. But that can be done with 3rd party programs (see my above post).
I now use fullscreen only when games take into account my Nvidia Control Panel settings.