diff --git a/qt4/style/qtcurve.h b/qt4/style/qtcurve.h
--- a/qt4/style/qtcurve.h
+++ b/qt4/style/qtcurve.h
@@ -436,9 +436,10 @@
     mutable const QWidget *m_sbWidget;
     mutable QLabel *m_clickedLabel;
     QSet<QProgressBar*> m_progressBars;
-    int m_progressBarAnimateTimer,
+    mutable int m_progressBarAnimateTimer,
+        m_progressBarAnimateFps,
         m_animateStep;
-    QTime m_timer;
+    mutable QTime m_timer;
     mutable QMap<int, QColor*> m_titleBarButtonsCols;
     mutable QList<int> m_mdiButtons[2]; // 0=left, 1=right
     mutable int m_titlebarHeight;
diff --git a/qt4/style/qtcurve.cpp b/qt4/style/qtcurve.cpp
--- a/qt4/style/qtcurve.cpp
+++ b/qt4/style/qtcurve.cpp
@@ -2694,10 +2694,15 @@
             if(bar)
             {
                 m_progressBars.insert(bar);
-                if (1==m_progressBars.size())
-                {
-                    m_timer.start();
-                    m_progressBarAnimateTimer = startTimer(1000 / constProgressBarFps);
+                if (!m_progressBarAnimateTimer) {
+                    if (opts.animatedProgress || (0 == bar->minimum() && 0 == bar->maximum())) {
+                        // we know we'll need a timer, start it at once
+                        if (m_timer.isNull()) {
+                            m_timer.start();
+                        }
+                        m_progressBarAnimateFps = constProgressBarFps;
+                        m_progressBarAnimateTimer = startTimer(1000/m_progressBarAnimateFps);
+                    }
                 }
             } else if(!POPUP_MENUS_SQUARE(opts) &&
                       object->inherits("QComboBoxPrivateContainer")) {
@@ -2729,6 +2734,7 @@
             }
             break;
         }
+        case QEvent::Close:
         case QEvent::Destroy:
         case QEvent::Hide: {
             if((BLEND_TITLEBAR || opts.windowBorder&WINDOW_BORDER_USE_MENUBAR_COLOR_FOR_TITLEBAR || opts.menubarHiding&HIDE_KWIN) &&
@@ -2821,15 +2827,22 @@
 void Style::timerEvent(QTimerEvent *event)
 {
     if (event->timerId() == m_progressBarAnimateTimer) {
+        bool hasAnimation = false;
         m_animateStep = m_timer.elapsed() / (1000 / constProgressBarFps);
         foreach (QProgressBar *bar, const_(m_progressBars)) {
             if ((opts.animatedProgress && 0 == m_animateStep % 2 &&
                  bar->value() != bar->minimum() &&
                  bar->value() != bar->maximum()) ||
                 (0 == bar->minimum() && 0 == bar->maximum())) {
                 bar->update();
+                hasAnimation = true;
             }
         }
+        if (Q_UNLIKELY(!hasAnimation && m_progressBarAnimateFps == constProgressBarFps)) {
+            // go back to "idling frequency" mode.
+            killTimer(m_progressBarAnimateTimer);
+            m_progressBarAnimateTimer = 0;
+        }
     }
 
     event->ignore();
@@ -5915,6 +5928,15 @@
 
                 painter->save();
 
+                if (!m_progressBarAnimateTimer && (opts.animatedProgress || indeterminate)) {
+                    if (m_timer.isNull()) {
+                        m_timer.start();
+                    }
+                    // now we'll need a timer, start it at the regular frequency
+                    m_progressBarAnimateFps = constProgressBarFps;
+                    m_progressBarAnimateTimer = const_cast<Style*>(this)->startTimer(1000/m_progressBarAnimateFps);
+                }
+
                 if(indeterminate) //Busy indicator
                 {
                     int chunkSize(PROGRESS_CHUNK_WIDTH*3.4),
diff --git a/qt5/style/qtcurve.h b/qt5/style/qtcurve.h
--- a/qt5/style/qtcurve.h
+++ b/qt5/style/qtcurve.h
@@ -556,9 +556,10 @@
     mutable const QWidget *m_sbWidget;
     mutable QLabel *m_clickedLabel;
     QSet<QProgressBar*> m_progressBars;
-    int m_progressBarAnimateTimer,
+    mutable int m_progressBarAnimateTimer,
+        m_progressBarAnimateFps,
         m_animateStep;
-    QTime m_timer;
+    mutable QTime m_timer;
     mutable QMap<int, QColor*> m_titleBarButtonsCols;
     mutable QList<int> m_mdiButtons[2]; // 0=left, 1=right
     mutable int m_titlebarHeight;
diff --git a/qt5/style/qtcurve_api.cpp b/qt5/style/qtcurve_api.cpp
--- a/qt5/style/qtcurve_api.cpp
+++ b/qt5/style/qtcurve_api.cpp
@@ -1313,10 +1313,15 @@
         if(bar)
         {
             m_progressBars.insert(bar);
-            if (1==m_progressBars.size())
-            {
-                m_timer.start();
-                m_progressBarAnimateTimer = startTimer(1000 / constProgressBarFps);
+            if (!m_progressBarAnimateTimer) {
+                if (opts.animatedProgress || (0 == bar->minimum() && 0 == bar->maximum())) {
+                    // we know we'll need a timer, start it at once
+                    if (m_timer.isNull()) {
+                        m_timer.start();
+                    }
+                    m_progressBarAnimateFps = constProgressBarFps;
+                    m_progressBarAnimateTimer = startTimer(1000/m_progressBarAnimateFps);
+                }
             }
         } else if (!(opts.square & SQUARE_POPUP_MENUS) &&
                    object->inherits("QComboBoxPrivateContainer")) {
@@ -1351,6 +1356,7 @@
         }
         break;
     }
+    case QEvent::Close:
     case QEvent::Destroy:
     case QEvent::Hide: {
         if ((BLEND_TITLEBAR ||
@@ -1420,15 +1426,22 @@
 void Style::timerEvent(QTimerEvent *event)
 {
     if (event->timerId() == m_progressBarAnimateTimer) {
+        bool hasAnimation = false;
         m_animateStep = m_timer.elapsed() / (1000 / constProgressBarFps);
         for (QProgressBar *bar: const_(m_progressBars)) {
             if ((opts.animatedProgress && 0 == m_animateStep % 2 &&
                  bar->value() != bar->minimum() &&
                  bar->value() != bar->maximum()) ||
                 (0 == bar->minimum() && 0 == bar->maximum())) {
                 bar->update();
+                hasAnimation = true;
             }
         }
+        if (Q_UNLIKELY(!hasAnimation && m_progressBarAnimateFps == constProgressBarFps)) {
+            // go back to "idling frequency" mode.
+            killTimer(m_progressBarAnimateTimer);
+            m_progressBarAnimateTimer = 0;
+        }
     }
 
     event->ignore();
@@ -2816,6 +2829,15 @@
 
             painter->save();
 
+            if (!m_progressBarAnimateTimer && (opts.animatedProgress || indeterminate)) {
+                if (m_timer.isNull()) {
+                    m_timer.start();
+                }
+                // now we'll need a timer, start it at the regular frequency
+                m_progressBarAnimateFps = constProgressBarFps;
+                m_progressBarAnimateTimer = const_cast<Style*>(this)->startTimer(1000/m_progressBarAnimateFps);
+            }
+
             if (indeterminate) {
                 //Busy indicator
                 int chunkSize = PROGRESS_CHUNK_WIDTH * 3.4;