diff --git a/src/mame/nmk/nmk16.cpp b/src/mame/nmk/nmk16.cpp
index 0a371088ac3..b61825e59c5 100644
--- a/src/mame/nmk/nmk16.cpp
+++ b/src/mame/nmk/nmk16.cpp
@@ -3886,7 +3886,7 @@ void nmk16_state::set_hacky_screen_hires(machine_config &config)
 
 	NMK_16BIT_SPRITE(config, m_spritegen, XTAL(16'000'000)/2);
 	m_spritegen->set_screen_size(28+412, 16+240);
-	m_spritegen->set_max_sprite_clock(384 * 263); // not verified?
+	m_spritegen->set_max_sprite_clock(512 * 263); // not verified?
 	m_spritegen->set_videoshift(28+64);
 }