diff --git a/src/mame/drivers/twin16.c b/src/mame/drivers/twin16.c
index 34b5dff0779..7aaa556a9a3 100644
--- a/src/mame/drivers/twin16.c
+++ b/src/mame/drivers/twin16.c
@@ -746,7 +746,7 @@ static MACHINE_CONFIG_START( twin16, twin16_state )
 	MCFG_MACHINE_RESET(twin16)
 
 	// video hardware
-	MCFG_VIDEO_ATTRIBUTES(VIDEO_HAS_SHADOWS | VIDEO_BUFFERS_SPRITERAM)
+	MCFG_VIDEO_ATTRIBUTES(VIDEO_HAS_SHADOWS | VIDEO_BUFFERS_SPRITERAM | VIDEO_UPDATE_AFTER_VBLANK)
 
 	MCFG_SCREEN_ADD("screen", RASTER)
 	MCFG_SCREEN_REFRESH_RATE(((double)XTAL_18_432MHz / 2) / (576 * 264))
@@ -799,7 +799,7 @@ static MACHINE_CONFIG_START( fround, twin16_state )
 	MCFG_MACHINE_RESET(twin16)
 
 	/* video hardware */
-	MCFG_VIDEO_ATTRIBUTES(VIDEO_HAS_SHADOWS | VIDEO_BUFFERS_SPRITERAM)
+	MCFG_VIDEO_ATTRIBUTES(VIDEO_HAS_SHADOWS | VIDEO_BUFFERS_SPRITERAM | VIDEO_UPDATE_AFTER_VBLANK)
 
 	MCFG_SCREEN_ADD("screen", RASTER)
 	MCFG_SCREEN_REFRESH_RATE(60)