Keeps dGPU on but idle until needed. This addresses the Windows 10 stutter/mouse freeze on dual GPU laptops. TrayPwrD3 runs in the background and stays in a tray icon. 
Other functionality: single click turns monitor off to save power until you wake it up by moving the mouse or using the keyboard; provides several menu options on right click; more details in Help menu.
This is to address the Windows 10 and Optimus problem of stutters and mouse hangs. For more about this issue see description on answers.microsoft Intel + NVIDIA Laptop Freeze Problem. Note: it is not for stutters in games. It only addresses the desktop stutters in Windows 10 (right click -> display settings, battery icon, chrome and firefox tabs, PowerPoint slideshow etc). If you don't have any of these, then you don't need it.
Simply download the executable, uncompress it in any folder and run it. Notes:
- The executable was compliled for 64bit windows.
- Direct3D version 12 is required.
- If you don't already have Visual C++ Redistributable for Visual Studio 2015 installed, then you could download and install it from Microsoft here.)
- Optional: If you would like to start TrayPwrD3 when windows starts, you can place a shortcut of the executable in the startup folder (located at %USERPROFILE%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\STARTUP). You can quickly open the startup folder by tapping the Windows key+R to bring up the "Run" dialog, and type
shell:startupthen enter.
When you start the program it simply runs in the background in a tray icon, keeping the dGPU on but idle. This addresses the well known Windows 10 stutter/mouse freeze on some dual GPU laptops.
To stop the program simpley right-click the icon and click exit. There is no need to reboot the system.
Tray icon:
Right click menu: 