Index: /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPMisc.cpp
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPMisc.cpp	(revision 60588)
+++ /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPMisc.cpp	(revision 60589)
@@ -1969,23 +1969,16 @@
         {
             VSyncTime.QuadPart = VSyncTime.QuadPart - DevVSyncTime.QuadPart;
-            /* Check whether we are in VBlank state or actively drawing a scan line
+            /*
+             * Check whether we are in VBlank state or actively drawing a scan line
              * 10% of the 60Hz are dedicated to VBlank.
+             *
+             * Time intervals are in 100ns steps.
              */
             LARGE_INTEGER VSyncPeriod;
             VSyncPeriod.QuadPart = VSyncTime.QuadPart % 166666LL; /* ASSUMES 60Hz*/
-            if (VSyncPeriod.QuadPart > 150000LL)
+            if (VSyncPeriod.QuadPart >= 150000LL)
                 bVBlank = TRUE;
             else
-            {
-                /* time is in 100ns, */
                 curScanLine = (uint32_t)((pTarget->Size.cy * VSyncPeriod.QuadPart) / 150000LL);
-                if (pDevExt->bVSyncTimerEnabled)
-                {
-                    if (curScanLine > pTarget->Size.cy)
-                        curScanLine = pTarget->Size.cy;
-                }
-                else
-                    curScanLine %= pTarget->Size.cy;
-            }
         }