diff --git a/main_x11.cpp b/main_x11.cpp
--- a/main_x11.cpp
+++ b/main_x11.cpp
@@ -43,6 +43,7 @@
 #include <QFile>
 #include <QLabel>
 #include <QPushButton>
+#include <QSurfaceFormat>
 #include <QVBoxLayout>
 #include <QX11Info>
 
@@ -417,6 +418,11 @@
     KWin::Application::createAboutData();
     KQuickAddons::QtQuickSettings::init();
 
+    // disables vsync for any QtQuick windows we create (BUG 406180)
+    QSurfaceFormat format = QSurfaceFormat::defaultFormat();
+    format.setSwapInterval(0);
+    QSurfaceFormat::setDefaultFormat(format);
+
     QCommandLineOption replaceOption(QStringLiteral("replace"), i18n("Replace already-running ICCCM2.0-compliant window manager"));
 
     QCommandLineParser parser;