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High cpu load on Windows 7 64 bit

  • Hi,
    my released Qt Quick 2 application consumes nearly whole CPU on Windows 7 64 bit (on Windows 8 and 10 it consumes max 1 % of CPU).

    Also on Windows 7 64 bit, the program starts with system warning that it cannot find api-ms-win-core-libraryloader-l1-2-0.dll (however, the program starts then). This issue might be related to high cpu load.

    Can you please advise? I use Qt 5.6 prebuilt mingw binaries and the system has DirectX 10.1.

  • The system is WIndow 7 Home Premium SP1, 64 bit
    OpenGL version 3.1
    DirectX version 9.0c - February 2010, 10.1
    (as displayed by OpenGL Extensions Viewer 4.44)
    I use mingw Qt 5.6.0

    When I set Qt::AA_UseDesktopOpenGL attribute in my application, then the app runs smoothly.

    When I set Qt::AA_UseOpenGLES then I get errors during the program launch:

    api-ms-win-core-libraryloader-l1-2-0.dll missing (at least 10 times)
    Failed to create OpenGL context for format QSurfaceFormat......

    The program crashes.

    When I set Qt::AA_UseSoftwareOpenGL then the program runs, but it of course consumes a lot of CPU.

    When I set none of mentioned attributes, then I get 4 times api-ms-win-core-libraryloader-l1-2-0.dll missing error and then the program runs but it consumes a lot of CPU (it seems the program tries to use Qt::AA_UseOpenGLES but it falls back to Qt::AA_UseSoftwareOpenGL).

    The program will run on a variety of systems and I don't want to force my users to manually select the graphics engine to use.

    Is there any solution to the issue?

  • Lifetime Qt Champion


    I don't know how the check is currently done for the dynamic selection of the backend. I'd recommend taking a look at the bug report system to see if there's something about it.

    You can also bring this topic to the interest mailing list. You'll find there Qt's developers/maintainers. This forum is more user oriented.

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