diff --git a/BasiliskII/ChangeLog b/BasiliskII/ChangeLog
index 94b9682a..23e84b5c 100644
--- a/BasiliskII/ChangeLog
+++ b/BasiliskII/ChangeLog
@@ -1,3 +1,7 @@
+V0.9 - <date>
+	- Unix: some performance improvements to VOSF screen update code
+	  [Brian J. Johnson]
+
 V0.9 (snapshot) - 17.Feb.2001
 	- adapted for mon V3.0 which is now the required minimum
 	- UAE cpu: fixed a bug in the memory handlers preventing from
diff --git a/BasiliskII/src/Unix/aclocal.m4 b/BasiliskII/src/Unix/aclocal.m4
index 3243d88f..83e412d9 100644
--- a/BasiliskII/src/Unix/aclocal.m4
+++ b/BasiliskII/src/Unix/aclocal.m4
@@ -370,3 +370,40 @@ int main ()
   rm -f conf.esdtest
 ])
 
+dnl AM_ESD_SUPPORTS_MULTIPLE_RECORD([ACTION-IF-SUPPORTS [, ACTION-IF-NOT-SUPPORTS]])
+dnl Test, whether esd supports multiple recording clients (version >=0.2.21)
+dnl
+AC_DEFUN(AM_ESD_SUPPORTS_MULTIPLE_RECORD,
+[dnl
+  AC_MSG_NOTICE([whether installed esd version supports multiple recording clients])
+  ac_save_ESD_CFLAGS="$ESD_CFLAGS"
+  ac_save_ESD_LIBS="$ESD_LIBS"
+  AM_PATH_ESD(0.2.21,
+    ifelse([$1], , [
+      AM_CONDITIONAL(ESD_SUPPORTS_MULTIPLE_RECORD, true)
+      AC_DEFINE(ESD_SUPPORTS_MULTIPLE_RECORD, 1,
+	[Define if you have esound with support of multiple recording clients.])],
+    [$1]),
+    ifelse([$2], , [AM_CONDITIONAL(ESD_SUPPORTS_MULTIPLE_RECORD, false)], [$2])
+    if test "x$ac_save_ESD_CFLAGS" != x ; then
+       ESD_CFLAGS="$ac_save_ESD_CFLAGS"
+    fi
+    if test "x$ac_save_ESD_LIBS" != x ; then
+       ESD_LIBS="$ac_save_ESD_LIBS"
+    fi
+  )
+])
+
+# Define a conditional.
+
+AC_DEFUN(AM_CONDITIONAL,
+[AC_SUBST($1_TRUE)
+AC_SUBST($1_FALSE)
+if $2; then
+  $1_TRUE=
+  $1_FALSE='#'
+else
+  $1_TRUE='#'
+  $1_FALSE=
+fi])
+
diff --git a/BasiliskII/src/Unix/video_vosf.h b/BasiliskII/src/Unix/video_vosf.h
index 32711f30..bde296ed 100644
--- a/BasiliskII/src/Unix/video_vosf.h
+++ b/BasiliskII/src/Unix/video_vosf.h
@@ -227,89 +227,31 @@ static inline void update_display_window_vosf(void)
 		
 		const int bytes_per_row = VideoMonitor.bytes_per_row;
 		const int bytes_per_pixel = VideoMonitor.bytes_per_row / VideoMonitor.x;
-		int i, j;
+		int i = y1 * bytes_per_row, j;
 		
-		// Check for first column from left and first column
-		// from right that have changed
-		int x1, x2, width;
 		if (depth == 1) {
 
-			x1 = VideoMonitor.x - 1;
-			for (j = y1; j <= y2; j++) {
-				uint8 * const p1 = &the_buffer[j * bytes_per_row];
-				uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
-				for (i = 0; i < (x1>>3); i++) {
-					if (p1[i] != p2[i]) {
-						x1 = i << 3;
-						break;
-					}
-				}
-			}
-
-			x2 = x1;
-			for (j = y2; j >= y1; j--) {
-				uint8 * const p1 = &the_buffer[j * bytes_per_row];
-				uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
-				for (i = (VideoMonitor.x>>3) - 1; i > (x2>>3); i--) {
-					if (p1[i] != p2[i]) {
-						x2 = (i << 3) + 7;
-						break;
-					}
-				}
-			}
-			width = x2 - x1 + 1;
-
 			// Update the_host_buffer and copy of the_buffer
-			i = y1 * bytes_per_row + (x1 >> 3);
 			for (j = y1; j <= y2; j++) {
-				Screen_blit(the_host_buffer + i, the_buffer + i, width >> 3);
-				memcpy(the_buffer_copy + i, the_buffer + i, width >> 3);
+				Screen_blit(the_host_buffer + i, the_buffer + i, VideoMonitor.x >> 3);
 				i += bytes_per_row;
 			}
 
 		} else {
 
-			x1 = VideoMonitor.x * bytes_per_pixel - 1;
-			for (j = y1; j <= y2; j++) {
-				uint8 * const p1 = &the_buffer[j * bytes_per_row];
-				uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
-				for (i = 0; i < x1; i++) {
-					if (p1[i] != p2[i]) {
-						x1 = i;
-						break;
-					}
-				}
-			}
-			x1 /= bytes_per_pixel;
-		
-			x2 = x1 * bytes_per_pixel;
-			for (j = y2; j >= y1; j--) {
-				uint8 * const p1 = &the_buffer[j * bytes_per_row];
-				uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
-				for (i = VideoMonitor.x * bytes_per_pixel - 1; i > x2; i--) {
-					if (p1[i] != p2[i]) {
-						x2 = i;
-						break;
-					}
-				}
-			}
-			x2 /= bytes_per_pixel;
-			width = x2 - x1 + 1;
-
 			// Update the_host_buffer and copy of the_buffer
-			i = y1 * bytes_per_row + x1 * bytes_per_pixel;
 			for (j = y1; j <= y2; j++) {
-				Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * width);
-				memcpy(the_buffer_copy + i, the_buffer + i, bytes_per_pixel * width);
+				Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * VideoMonitor.x);
 				i += bytes_per_row;
 			}
 		}
-		
+
 		if (have_shm)
-			XShmPutImage(x_display, the_win, the_gc, img, x1, y1, x1, y1, width, height, 0);
+			XShmPutImage(x_display, the_win, the_gc, img, 0, y1, 0, y1, VideoMonitor.x, height, 0);
 		else
-			XPutImage(x_display, the_win, the_gc, img, x1, y1, x1, y1, width, height);
+			XPutImage(x_display, the_win, the_gc, img, 0, y1, 0, y1, VideoMonitor.x, height);
 	}
+
 	mainBuffer.dirty = false;
 }
 
diff --git a/BasiliskII/src/Unix/video_x.cpp b/BasiliskII/src/Unix/video_x.cpp
index ad3201f7..5f597c47 100644
--- a/BasiliskII/src/Unix/video_x.cpp
+++ b/BasiliskII/src/Unix/video_x.cpp
@@ -2053,6 +2053,7 @@ static void video_refresh_window_vosf(void)
 			LOCK_VOSF;
 			update_display_window_vosf();
 			UNLOCK_VOSF;
+			XSync(x_display, false); // Let the server catch up
 		}
 	}
 }
@@ -2140,7 +2141,7 @@ static void *redraw_func(void *arg)
 		ticks++;
 	}
 	uint64 end = GetTicks_usec();
-	printf("%Ld ticks in %Ld usec = %Ld ticks/sec\n", ticks, end - start, ticks * 1000000 / (end - start));
+	// printf("%Ld ticks in %Ld usec = %Ld ticks/sec\n", ticks, end - start, ticks * 1000000 / (end - start));
 	return NULL;
 }
 #endif