QML XYSeries (LineSeries, etc..) looks less sharp with useOpenGL enabled on embedded device

Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    ChartView {
        title: "Line Chart"
        anchors.fill: parent
        antialiasing: true

        LineSeries {
            useOpenGL: true
            name: "Line"

            XYPoint {
                x: 0
                y: 0
            }

            XYPoint {
                x: 1.1
                y: 2.1
            }

            XYPoint {
                x: 1.9
                y: 3.3
            }

            XYPoint {
                x: 2.1
                y: 2.1
            }

            XYPoint {
                x: 2.9
                y: 4.9
            }

            XYPoint {
                x: 3.4
                y: 3
            }

            XYPoint {
                x: 4.1
                y: 3.3
            }

        }
    }
}