Bem-vindos ao GTA5-Mods.com

@Steambun Seems like DirectX hooking is a possible solution, it can performance greatly on many systems (if memory serves, this is the same method fraps uses to do both displaying fps and capturing). But it's not the nicest and the easiest to implement.

The current method is really great, the 50% fps drop is inevitable anyway due to camera re-positioning. But it really needs you to run the main game (without the split screens) at least in 120 fps in order to get satisfying results.

@Hushbrown Back when I made that comment, I didn't have any idea about how this mod achieved this effect.

It seems like there are no 3 windows, but 2. The main window (GTA V), and the overlay created by the mod which has enough width to host both images (P1 and P2 camera render).

I'm not entirely sure, but the dev has used BitBlt winapi in order to capture the window. While this remains a great choice, the following should have been mentioned as well:

* This function's performance is extremely slow if AERO and DWM are enabled.
* This function's performance varies from system to another because it also calls a function in the device driver.

(Disclaimer: This was tested on Win7)

AERO can be disabled by switching to Basic/Classic theme, DWM can be disabled by stopping its service.
After disabling them I could see a little improvement but not that much since the max I can get is 60~70 fps in-game.

@Noddus I also have 1366x768 monitors, I've modified the mod to support this one, but not sure if such file can be shared.

@Steambun, Any idea why a third window appear in the middle? Behind the two screens, it heavily impacts performance.

The third window also has somewhat decent fps whereas the split screens have horrible fps. It (the thirs window) flickers a lot as well.

Screenshot:
https://imgur.com/0Ykzx8t