diff --git a/src/mame/drivers/seicross.c b/src/mame/drivers/seicross.c
index 972f81f8679..a2c9eff1222 100644
--- a/src/mame/drivers/seicross.c
+++ b/src/mame/drivers/seicross.c
@@ -408,7 +408,7 @@ static MACHINE_CONFIG_START( nvram, seicross_state )
 	MCFG_CPU_IO_MAP(main_portmap)
 	MCFG_CPU_VBLANK_INT("screen", vblank_irq)
 
-	MCFG_CPU_ADD("mcu", NSC8105, 6000000)	/* ??? */
+	MCFG_CPU_ADD("mcu", NSC8105, 3072000)	/* ??? */
 	MCFG_CPU_PROGRAM_MAP(mcu_nvram_map)
 
 	MCFG_QUANTUM_TIME(attotime::from_hz(1200))	/* 20 CPU slices per frame - an high value to ensure proper */