diff --git a/stella/Changes.txt b/stella/Changes.txt
index 97a9d33e8..024cb153f 100644
--- a/stella/Changes.txt
+++ b/stella/Changes.txt
@@ -30,6 +30,12 @@
     calculation.  Also, re-enabled changing the framerate from within the
     UI.
 
+  * Added '-timing' commandline argument, which sets the type of waiting
+    between processing frames.  Setting it to 'sleep' emulates the
+    previous behaviour in Stella; setting it to 'busy' emulates z26,
+    and can in some cases eliminate screen tearing (at the expense of
+    using all available CPU time).
+
   * Fixed issue with debugger disassembly and mirrored $40 TIA write
     addresses.  They were actually defined at $30, and generating incorrect
     labels.
diff --git a/stella/docs/index.html b/stella/docs/index.html
index 36b502d9d..81ea2d38b 100644
--- a/stella/docs/index.html
+++ b/stella/docs/index.html
@@ -240,6 +240,12 @@
     calculation.  Also, re-enabled changing the framerate from within the
     UI.</li>
 
+<li>Added '-timing' commandline argument, which sets the type of waiting
+    between processing frames.  Setting it to 'sleep' emulates the
+    previous behaviour in Stella; setting it to 'busy' emulates z26,
+    and can in some cases eliminate screen tearing (at the expense of
+    using all available CPU time).</li>
+
 <li>Fixed issue with debugger disassembly and mirrored $40 TIA write
     addresses.  They were actually defined at $30, and generating incorrect
     labels.</li>
@@ -657,6 +663,16 @@
 			<td>Enable/disable the PAL color-loss effect.</td>
 		</tr>
 
+		<tr>
+			<td><pre>-timing &lt;sleep|busy&gt;</pre></td>
+			<td>Determines type of wait to perform between processing frames.
+				Sleep will release the CPU as much as possible, and is the
+				preferred method on laptops (and other low-powered devices)
+				and when using GL VSync.  Busy will emulate z26 busy-wait
+				behaviour, and use all possible CPU time, but may eliminate
+				graphical 'tearing'.</td>
+		</tr>
+
 		<tr>
 			<td><pre>-framerate &lt;number&gt;</pre></td>
 			<td>Display the given number of frames per second.  Normally, Stella
diff --git a/stella/src/emucore/OSystem.cxx b/stella/src/emucore/OSystem.cxx
index 54ef61009..da4d27525 100644
--- a/stella/src/emucore/OSystem.cxx
+++ b/stella/src/emucore/OSystem.cxx
@@ -13,7 +13,7 @@
 // See the file "license" for information on usage and redistribution of
 // this file, and for a DISCLAIMER OF ALL WARRANTIES.
 //
-// $Id: OSystem.cxx,v 1.128 2008-05-21 14:50:41 stephena Exp $
+// $Id: OSystem.cxx,v 1.129 2008-05-21 16:49:07 stephena Exp $
 //============================================================================
 
 #include <cassert>
@@ -797,20 +797,42 @@ void OSystem::stateChanged(EventHandler::State state)
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void OSystem::mainLoop()
 {
-  for(;;)
+  if(mySettings->getString("timing") == "sleep")
   {
-    myTimingInfo.start = getTicks();
-    myEventHandler->poll(myTimingInfo.start);
-    if(myQuitLoop) break;  // Exit if the user wants to quit
-    myFrameBuffer->update();
-    myTimingInfo.current = getTicks();
-    myTimingInfo.virt += myTimePerFrame;
+    // Sleep-based wait: good for CPU, bad for graphical sync
+    for(;;)
+    {
+      myTimingInfo.start = getTicks();
+      myEventHandler->poll(myTimingInfo.start);
+      if(myQuitLoop) break;  // Exit if the user wants to quit
+      myFrameBuffer->update();
+      myTimingInfo.current = getTicks();
+      myTimingInfo.virt += myTimePerFrame;
 
-    if(myTimingInfo.current < myTimingInfo.virt)
-      SDL_Delay((myTimingInfo.virt - myTimingInfo.current) / 1000);
+      if(myTimingInfo.current < myTimingInfo.virt)
+        SDL_Delay((myTimingInfo.virt - myTimingInfo.current) / 1000);
 
-    myTimingInfo.totalTime += (getTicks() - myTimingInfo.start);
-    myTimingInfo.totalFrames++;
+      myTimingInfo.totalTime += (getTicks() - myTimingInfo.start);
+      myTimingInfo.totalFrames++;
+    }
+  }
+  else
+  {
+    // Busy-wait: bad for CPU, good for graphical sync
+    for(;;)
+    {
+      myTimingInfo.start = getTicks();
+      myEventHandler->poll(myTimingInfo.start);
+      if(myQuitLoop) break;  // Exit if the user wants to quit
+      myFrameBuffer->update();
+      myTimingInfo.virt += myTimePerFrame;
+
+      while(getTicks() < myTimingInfo.virt)
+        ;  // busy-wait
+
+      myTimingInfo.totalTime += (getTicks() - myTimingInfo.start);
+      myTimingInfo.totalFrames++;
+    }
   }
 }
 
diff --git a/stella/src/emucore/Settings.cxx b/stella/src/emucore/Settings.cxx
index afa17eb9d..507f6fd9d 100644
--- a/stella/src/emucore/Settings.cxx
+++ b/stella/src/emucore/Settings.cxx
@@ -13,7 +13,7 @@
 // See the file "license" for information on usage and redistribution of
 // this file, and for a DISCLAIMER OF ALL WARRANTIES.
 //
-// $Id: Settings.cxx,v 1.146 2008-05-21 14:01:30 stephena Exp $
+// $Id: Settings.cxx,v 1.147 2008-05-21 16:49:07 stephena Exp $
 //============================================================================
 
 #include <cassert>
@@ -55,6 +55,7 @@ Settings::Settings(OSystem* osystem)
   setInternal("grabmouse", "false");
   setInternal("palette", "standard");
   setInternal("colorloss", "false");
+  setInternal("timing", "sleep");
 
   // Sound options
   setInternal("sound", "true");
@@ -214,6 +215,10 @@ void Settings::validate()
   if(s != "soft" && s != "gl")
     setInternal("video", "soft");
 
+  s = getString("timing");
+  if(s != "sleep" && s != "busy")
+    setInternal("timing", "sleep");
+
 #ifdef DISPLAY_OPENGL
   s = getString("gl_filter");
   if(s != "linear" && s != "nearest")
@@ -308,6 +313,7 @@ void Settings::usage()
     << "                 user>\n"
     << "  -colorloss    <1|0>          Enable PAL color-loss effect\n"
     << "  -framerate    <number>       Display the given number of frames per second (0 to auto-calculate)\n"
+    << "  -timing       <sleep|busy>   Use the given type of wait between frames\n"
     << endl
   #ifdef SOUND_SUPPORT
     << "  -sound        <1|0>          Enable sound generation\n"