To get max frame rate the screen does not have to exist in any frame buffer which recording apps use to get the image.
I'm sure you have found prior discussions and this is not a new issue or unique. This is why those that want to record game play go with whatever works.
I've recently bought a new custom build PC, with NVidia GTX 770, i7 4770 processor and running Win 7 x64.
For some time now I have investigated a problem that occurs to me while trying to record game applications. Let me start by saying that I have tried using several different screen recording softwares, including Camstudio, BB FlashBack, Ezvid, Xsplit, Fraps and some others, and all of them behave in exactly the same way and the issue seems to reoccur with all of them, so I strongly doubt that the problem is caused by the recording software. The desktop records perfectly well, regardless of the win 7 aero settings being on or off and with both 16 and 32 bit graphic settings. When I tried to record games (tried with Neverwinter 1 and 2, The Witcher, Euro Truck Simulator Assassins Creed 2 and 3) the second the game application takes over desktop on the recording I can only see a black image. Game sound records perfectly, sometimes I even get a glimpse of game cursor, but the rest is the deepest and blackest blackness. After researching a bit I tried to play with NVidia control panel's 3D settings, but this did not seem to work (although I'm not a pro so may have missed something there).
Interestingly, it's a problem with recording full screen applications only, as when I run a game in windowed mode it records well! Have just tried different resolutions, desktop and in-game, all give the same poor result. So there must be something between windowed mode and full-screen mode that makes all the difference. No clue what that would be though.
Also going through other forums researching the issue, I found this sentence. May this be the key?
" When a game is truly full-screen, it doesn't have to play nice and share resources with other applications running; it has full, total control over what gets painted to the screen. This lets the graphics card cut some corners, increasing frame-rate."
Any input on the problem will be much appreciated. If any more information is needed, please let me know and I'll supply it.
Thanks in advance.