Keeps dGPU on but idle until needed. This addresses the Windows 10 (64bit) stutter/mouse freeze on dual GPU laptops (intel or AMD CPU with built in GPU in combination with NVIDIA). 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.
Windows 10 May 2020 Update: With this latest update Microsoft fixed the latency issue. However, you will need NVIDIA driver version 451.48 or later. For more information see this Windows Latest post: Nvidia GeForce 451.48 adds Windows 10 GPU scheduling feature.
Update 7/14/2020: Still noticing some brief hanging during some activities with explorer. So latency issue not totally fixed.
Update 11/12/2020: Still noticing some major hanging during some activities with explorer and when running certain apps e.g. Media Player Classic on AMD Ryzen systems. So NVIDIA GPU activation latency remains a problem. The updated version of TrayPwrD3 (v2020-11) now supports AMD Ryzen systems and prevents the GPU stutter or latency on both Intel and AMD Ryzen systems.
Update 12/25/2025: Starting the app now checks if there is a running instance and gives the option to kill it.
Simply download the latest version of 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 installed, then you could download the 64bit version directly from Microsoft and install it.
- 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 app 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 app simpley right-click the icon and click exit. There is no need to reboot the system.
Tray icon:
Right click menu: 