diff --git a/common/rfb/VNCServer.h b/common/rfb/VNCServer.h
index 314367eb6..b49dbfe34 100644
--- a/common/rfb/VNCServer.h
+++ b/common/rfb/VNCServer.h
@@ -43,6 +43,7 @@ namespace rfb {
     virtual void unblockUpdates() = 0;
 
     virtual uint64_t getMsc() = 0;
+    virtual void queueMsc(uint64_t target) = 0;
 
     // setPixelBuffer() tells the server to use the given pixel buffer (and
     // optionally a modified screen layout).  If this differs in size from
diff --git a/common/rfb/VNCServerST.cxx b/common/rfb/VNCServerST.cxx
index 296ddd8ed..f091ddd5d 100644
--- a/common/rfb/VNCServerST.cxx
+++ b/common/rfb/VNCServerST.cxx
@@ -88,7 +88,7 @@ VNCServerST::VNCServerST(const char* name_, SDesktop* desktop_)
     renderedCursorInvalid(false),
     keyRemapper(&KeyRemapper::defInstance),
     idleTimer(this), disconnectTimer(this), connectTimer(this),
-    msc(0), frameTimer(this)
+    msc(0), queuedMsc(0), frameTimer(this)
 {
   slog.debug("creating single-threaded server %s", name.c_str());
 
@@ -262,6 +262,14 @@ uint64_t VNCServerST::getMsc()
   return msc;
 }
 
+void VNCServerST::queueMsc(uint64_t target)
+{
+  if (target > queuedMsc)
+    queuedMsc = target;
+
+  startFrameClock();
+}
+
 void VNCServerST::setPixelBuffer(PixelBuffer* pb_, const ScreenSet& layout)
 {
   if (comparer)
@@ -634,13 +642,17 @@ void VNCServerST::handleTimeout(Timer* t)
 {
   if (t == &frameTimer) {
     // We keep running until we go a full interval without any updates
-    if (comparer->is_empty())
-      return;
+    if (comparer->is_empty()) {
+      // Unless something waits for us to advance the frame count
+      if (queuedMsc < msc)
+        return;
+    }
 
     // If this is the first iteration then we need to adjust the timeout
     frameTimer.repeat(1000/rfb::Server::frameRate);
 
-    writeUpdate();
+    if (!comparer->is_empty())
+      writeUpdate();
 
     msc++;
     desktop->frameTick(msc);
diff --git a/common/rfb/VNCServerST.h b/common/rfb/VNCServerST.h
index 719b3f366..3436d333f 100644
--- a/common/rfb/VNCServerST.h
+++ b/common/rfb/VNCServerST.h
@@ -82,6 +82,7 @@ namespace rfb {
     virtual void blockUpdates();
     virtual void unblockUpdates();
     virtual uint64_t getMsc();
+    virtual void queueMsc(uint64_t target);
     virtual void setPixelBuffer(PixelBuffer* pb, const ScreenSet& layout);
     virtual void setPixelBuffer(PixelBuffer* pb);
     virtual void setScreenLayout(const ScreenSet& layout);
@@ -207,7 +208,7 @@ namespace rfb {
     Timer disconnectTimer;
     Timer connectTimer;
 
-    uint64_t msc;
+    uint64_t msc, queuedMsc;
     Timer frameTimer;
   };
 
diff --git a/unix/xserver/hw/vnc/XserverDesktop.cc b/unix/xserver/hw/vnc/XserverDesktop.cc
index 6fe055ea3..eaf6f901b 100644
--- a/unix/xserver/hw/vnc/XserverDesktop.cc
+++ b/unix/xserver/hw/vnc/XserverDesktop.cc
@@ -154,6 +154,7 @@ uint64_t XserverDesktop::getMsc()
 void XserverDesktop::queueMsc(uint64_t id, uint64_t msc)
 {
   pendingMsc[id] = msc;
+  server->queueMsc(msc);
 }
 
 void XserverDesktop::abortMsc(uint64_t id)