diff --git a/OSBindings/Mac/Clock Signal/CSAtari2600.mm b/OSBindings/Mac/Clock Signal/CSAtari2600.mm
index b20b1f040..98edbed40 100644
--- a/OSBindings/Mac/Clock Signal/CSAtari2600.mm	
+++ b/OSBindings/Mac/Clock Signal/CSAtari2600.mm	
@@ -30,7 +30,7 @@ typedef NS_ENUM(NSInteger, CSAtari2600RunningState) {
 	dispatch_queue_t _serialDispatchQueue;
 
 	int _frameCount;
-	NSTimeInterval _startTimeInterval;
+	int _hitCount;
 	BOOL _didDecideRegion;
 
 	NSConditionLock *_runningLock;
@@ -40,28 +40,20 @@ typedef NS_ENUM(NSInteger, CSAtari2600RunningState) {
 
 	if(!_didDecideRegion)
 	{
-		if(_startTimeInterval < 1.0)
-		{
-			_startTimeInterval = [NSDate timeIntervalSinceReferenceDate];
-		}
-		else
-		{
-			_frameCount++;
+		_frameCount++;
+		_hitCount += didDetectVSync ? 1 : 0;
 
-			if(_frameCount > 30)
+		if(_frameCount > 30)
+		{
+			if(_hitCount < _frameCount >> 1)
 			{
-				float fps = (float)_frameCount / (float)([NSDate timeIntervalSinceReferenceDate] - _startTimeInterval);
+				_atari2600.switch_region();
+				_didDecideRegion = YES;
+			}
 
-				if(fabsf(fps - 50.0f) < 5.0f)
-				{
-					_atari2600.switch_region();
-					_didDecideRegion = YES;
-				}
-
-				if(fabsf(fps - 60.0f) < 5.0f)
-				{
-					_didDecideRegion = YES;
-				}
+			if(_hitCount > (_frameCount * 7) >> 3)
+			{
+				_didDecideRegion = YES;
 			}
 		}
 	}
diff --git a/OSBindings/Mac/Clock Signal/CSCathodeRayView.m b/OSBindings/Mac/Clock Signal/CSCathodeRayView.m
index ce0ebc03e..331324511 100644
--- a/OSBindings/Mac/Clock Signal/CSCathodeRayView.m	
+++ b/OSBindings/Mac/Clock Signal/CSCathodeRayView.m	
@@ -204,7 +204,7 @@ const char *fragmentShader =
 	"\n"
 	"void main(void)\n"
 	"{\n"
-		"fragColour = texture(texID, srcCoordinatesVarying) * vec4(1.0, 1.0, 1.0, sin(lateralVarying));\n" //
+		"fragColour = texture(texID, srcCoordinatesVarying) * vec4(1.0, 1.0, 1.0, 1.0);\n" // .a = sin(lateralVarying)
 	"}\n";
 
 #if defined(DEBUG)
diff --git a/Outputs/CRT.cpp b/Outputs/CRT.cpp
index 9bd2a50fd..e327d6a49 100644
--- a/Outputs/CRT.cpp
+++ b/Outputs/CRT.cpp
@@ -28,7 +28,7 @@ void CRT::set_new_timing(unsigned int cycles_per_line, unsigned int height_of_di
 	height_of_display += (height_of_display / 20);  // this is the overrun area we'll use to
 
 	// store fundamental display configuration properties
-	_height_of_display = height_of_display;
+	_height_of_display = height_of_display + 5;
 	_cycles_per_line = cycles_per_line * _time_multiplier;
 
 	// generate timing values implied by the given arbuments
@@ -37,7 +37,7 @@ void CRT::set_new_timing(unsigned int cycles_per_line, unsigned int height_of_di
 	_sync_capacitor_charge_threshold = ((syncCapacityLineChargeThreshold * _cycles_per_line) * 50) >> 7;
 	_horizontal_retrace_time = (millisecondsHorizontalRetraceTime * _cycles_per_line) >> 6;
 	const unsigned int vertical_retrace_time = scanlinesVerticalRetraceTime * _cycles_per_line;
-	const float halfLineWidth = (float)_height_of_display * 1.85f;
+	const float halfLineWidth = (float)_height_of_display * 2.0f;
 
 	for(int c = 0; c < 4; c++)
 	{
@@ -103,7 +103,7 @@ CRT::SyncEvent CRT::get_next_vertical_sync_event(bool vsync_is_requested, unsign
 
 	// will an acceptable vertical sync be triggered?
 	if (vsync_is_requested && !_is_in_vsync) {
-		if (_sync_capacitor_charge_level >= _sync_capacitor_charge_threshold && _rasterPosition.y >= (kCRTFixedPointRange >> 1)) {
+		if (_sync_capacitor_charge_level >= _sync_capacitor_charge_threshold && _rasterPosition.y >= 3*(kCRTFixedPointRange >> 2)) {
 			proposedSyncTime = 0;
 			proposedEvent = SyncEvent::StartVSync;
 			_did_detect_vsync = true;
@@ -112,12 +112,12 @@ CRT::SyncEvent CRT::get_next_vertical_sync_event(bool vsync_is_requested, unsign
 
 	// have we overrun the maximum permitted number of horizontal syncs for this frame?
 	if (!_is_in_vsync) {
-//		unsigned int time_until_end_of_frame = (kCRTFixedPointRange - _rasterPosition.y) / _scanSpeed[0].y;
-//
-//		if(time_until_end_of_frame < proposedSyncTime) {
-//			proposedSyncTime = time_until_end_of_frame;
-//			proposedEvent = SyncEvent::StartVSync;
-//		}
+		unsigned int time_until_end_of_frame = (kCRTFixedPointRange - _rasterPosition.y) / _scanSpeed[0].y;
+
+		if(time_until_end_of_frame < proposedSyncTime) {
+			proposedSyncTime = time_until_end_of_frame;
+			proposedEvent = SyncEvent::StartVSync;
+		}
 	} else {
 		unsigned int time_until_start_of_frame = _rasterPosition.y / (uint32_t)(-_scanSpeed[kRetraceYMask].y);
 
@@ -217,8 +217,8 @@ void CRT::advance_cycles(unsigned int number_of_cycles, bool hsync_requested, bo
 
 		// advance the raster position as dictated by current sync status
 		int64_t end_position[2];
-		end_position[0] = (int64_t)_rasterPosition.x + (int64_t)number_of_cycles * (int32_t)_scanSpeed[lengthMask].x;
-		end_position[1] = (int64_t)_rasterPosition.y + (int64_t)number_of_cycles * (int32_t)_scanSpeed[lengthMask].y;
+		end_position[0] = (int64_t)_rasterPosition.x + (int64_t)next_run_length * (int32_t)_scanSpeed[lengthMask].x;
+		end_position[1] = (int64_t)_rasterPosition.y + (int64_t)next_run_length * (int32_t)_scanSpeed[lengthMask].y;
 
 		if (_is_in_hsync)
 			_rasterPosition.x = (uint32_t)std::max((int64_t)0, end_position[0]);