You can run Dragon Age in maximized window without border by using a program called ShiftWindow. This pushes the window so that the edges are not seen by you monitor. I have a guide up on the net written up here:
Its also always less stable. There isn't a single game that acted "better" when alt tabed from full screen, than when just using windowed. There is either no difference, or windowed is better.
Its even more useful when the game takes a lot of juice, like Dragon Age on a weak computer. I occasionally crash just by alt tabing. Also, every alt tab I do seems to make the game run more slowly (actually, simple things, like when someone talks, take more times to load, its weird).
I've encountered so many problems like this when I have reasons to alt tab in many games, and running it windowed always helped.
Fullscreen windowed mode is the best there is, the end.