Qt 4.8 vs 5.3 for QML performance (embedded: no-OpenGL, soft-float)



  • Greetings all,

    My target platform is a iMX28 ARM 450Mhz SoC.
    It has no OpenGL and no hardware float ability.

    I have a QtQuick 1.1 proof of concept app currently using Qt 4.8.6.
    Using any of the QML transform animations brings the system to its knees... 100% CPU usage.
    (it seems the QML transforms are rendered at about 60fps(?) which is far too fast for this SoC)

    I've read a little about the changes to QtQuick in QT5, but am unsure how they would affect performance in this case.

    Should i stick with 4.8, or will the move to Qt5 help?

    Thanks in advance.



  • I'm not an expert but I know OpenGL is mandatory for Qt 5.0 and higher, so if your board doesn't support OpenGL for sure Qt 5.x will not work ...



  • Keep in mind that QtQuick 1 is still included in Qt 5 for compatibility reasons so you can still make use of it but the performance would be essentially identical to 4.8.

    It is also possible to deploy QtQuick 2 with a software opengl renderer based on llvmpipe but that is not neccessarily faster than 4.8. It is hard to tell without trying though.



  • Using a software opengl renderer doesnt sound like a good solution to me. I cant see how it would improve performance over 4.8.

    Im starting to think that QML in any form is too heavy for this ARM SoC.

    No matter what i try, i just cant get anything close to acceptable graphics performance.


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