diff --git a/src/osd.c b/src/osd.c
index e66a4d9d..699fd1e1 100644
--- a/src/osd.c
+++ b/src/osd.c
@@ -164,7 +164,8 @@ static const char *interpolation_names[] = {
 };
 
 static const char *vlockspeed_names[] = {
-   "Slow (1000PPM)",
+   "Slow (333PPM)", 
+   "Medium (1000PPM)",
    "Fast (2000PPM)"
 };
 
diff --git a/src/osd.h b/src/osd.h
index 6c12a712..2103cf85 100644
--- a/src/osd.h
+++ b/src/osd.h
@@ -102,6 +102,7 @@ enum {
 
 enum {
    VLOCKSPEED_SLOW,
+   VLOCKSPEED_MEDIUM,
    VLOCKSPEED_FAST,
    NUM_VLOCKSPEED
 };
diff --git a/src/rgb_to_hdmi.c b/src/rgb_to_hdmi.c
index 6f22f1da..1e780029 100644
--- a/src/rgb_to_hdmi.c
+++ b/src/rgb_to_hdmi.c
@@ -148,7 +148,7 @@ static int deinterlace = 6;
 static int vsync       = 0;
 static int vlockmode   = 1;
 static int vlockline   = 10;
-static int vlockspeed  = 1;
+static int vlockspeed  = 2;
 static int vlockadj    = 0;
 static int lines_per_frame = 0;
 static int one_line_time_ns = 0;
@@ -834,10 +834,16 @@ int recalculate_hdmi_clock_line_locked_update(int force) {
             int max_steps = GENLOCK_MAX_STEPS;
             int locked_threshold = GENLOCK_LOCKED_THRESHOLD;
             int frame_delay = GENLOCK_FRAME_DELAY;
-            if (vlockspeed == VLOCKSPEED_SLOW) {
+            if (vlockspeed == VLOCKSPEED_MEDIUM) {
                 max_steps >>= 1;
                 locked_threshold--;
                 frame_delay <<= 1;
+            } else {
+                if (vlockspeed == VLOCKSPEED_SLOW) {
+                    max_steps = 1;
+                    locked_threshold = 1;
+                    frame_delay <<= 1;
+                }
             }
             signed int difference = (vsync_line >> adjustment) - ((total_lines >> adjustment) - vlockline);
             if (abs(difference) > (total_lines >> (adjustment + 1))) {