Nominate our 2022 Qt Champions!

[solved] Qt Quick 2 performance issues

  • Hello, I started a new project in which I need to render Qml content on an WQHD display (2560 x 1440).
    And I'm still trying to get a pretty basic qml test to run fluently. But on the full resolution the rendering performance drops way below 10 fps.
    The target system runs a AMD G-T56N dual core processor 1,6 GHz 3,5 GiB ram and a dedicated AMD Radeon HD 6310 graphics card.

    My qml Test is nothing more than this:
    @import QtQuick 2.0

    Item {
    id: grid_view
    width: 800
    height: 600

    Rectangle {
        id: grid_view_bg
        anchors.fill: parent
        ListModel {
            id: employee_model
            ListElement { name: "User 1"; }
            ListElement { name: "User 2"; }
            ListElement { name: "User 3"; }
            ListElement { name: "User 4"; }
            ListElement { name: "User 5"; }
            ListElement { name: "User 6"; }
            ListElement { name: "User 7"; }
            ListElement { name: "User 8"; }
            ListElement { name: "User 9"; }
            ListElement { name: "User 10"; }
        Component {
            id: employeeDelegate
            Item {
                width: 180;
                height: 200
                Rectangle {
                    anchors.fill: parent
                    anchors.rightMargin: 5
                    color: "red"
                    border.color: "black"
                    Rectangle {
                        id: employeeHeader
                        color: "#bbdbf3"
                        anchors.horizontalCenter: parent.horizontalCenter
                        width: parent.width
                        height: 40
                        Text {
                            anchors.centerIn: parent
                            text: '<b>Name:</b> ' + name
                        border.color: "black"
        ListView {
            anchors.fill: parent
            model: employee_model
            orientation: Qt.Horizontal
            delegate: employeeDelegate


    The main.cpp:
    @QGuiApplication app(argc, argv);

    QtQuick2ApplicationViewer viewer;


    So I just used the predefined QtQuick 2 Application example to start with.
    Even on my development system running an intel quad core with dedicated ATI Radeon HD 3450 the performance start to decrease at a 1920 x 1080 resolution. The higher the resolution gets the worse is the performance. At the full WQHD resolution it is just unusable.

    What might be the problem here ?
    I would expect that qt is capable of a way better performance than what i get right now.
    Both cards support at least OpenGL 3 or higher.
    What can i do to get the qml animation on the list scrolling to run smooth.

    I could need some help with this one.
    Thank you for any help.

  • Moderators

    Are you using Qt 5.2? What OS are you on? Have you compiled Qt yourself (or maybe we are talking about an ANGLE build)?

    I think in Qt 5.2 you can bump the version number to QtQuick 2.1, BTW.

  • Hi,

    I'm using Qt 5.1.1 compiled by myself on Ubuntu on both systems.
    May there be any performance difference between 5.1.1 and 5.2 ?

  • Moderators

    Yes, the rendering engine has been significantly optimised (see "this": blog entry).

    If possible, compile Qt with "-opengl desktop" flag. It will make the most of your GPU.

  • Ok thanks I'm going to compile Qt 5.2 with the opengl desktop flag and see what happens.

  • Hey thanks for the hint sierdzio.
    It's amazing. On Qt5.2 the example runs so much better then with 5.1.1.
    Awesome piece the new scene graph.

    Thumbs up.

  • Moderators

    hey, great! I'm happy that it helped you :)

Log in to reply