diff --git a/OSBindings/Mac/Clock Signal/CSCathodeRayView.m b/OSBindings/Mac/Clock Signal/CSCathodeRayView.m
index a0bc9c7ea..c9435ad10 100644
--- a/OSBindings/Mac/Clock Signal/CSCathodeRayView.m	
+++ b/OSBindings/Mac/Clock Signal/CSCathodeRayView.m	
@@ -156,14 +156,15 @@ const char *vertexShader =
 	"\n"
 	"in vec2 position;\n"
 	"in vec2 srcCoordinates;\n"
+	"in float lateral;\n"
 	"\n"
 	"out vec2 srcCoordinatesVarying;\n"
-	"out float offsetVarying;\n"
+	"out float lateralVarying;\n"
 	"\n"
 	"void main (void)\n"
 	"{\n"
-		"srcCoordinatesVarying = vec2(srcCoordinates.x / 512.0, srcCoordinates.y / 512.0);\n"
-		"offsetVarying = mod(srcCoordinatesVarying.y * 512, 1.0) * 2.09435310266667 + 0.52359877566668;"
+		"srcCoordinatesVarying = vec2(srcCoordinates.x / 512.0, (srcCoordinates.y + 0.5) / 512.0);\n"
+		"lateralVarying = lateral * 2.09435310266667 + 0.52359877566668;"
 		"gl_Position = vec4(position.x * 2.0 - 1.0, 1.0 - position.y * 2.0 + position.x / 131.0, 0.0, 1.0);\n"
 	"}\n";
 
@@ -172,13 +173,13 @@ const char *fragmentShader =
 	"#version 150\n"
 	"\n"
 	"in vec2 srcCoordinatesVarying;\n"
-	"in float offsetVarying;"
+	"in float lateralVarying;"
 	"out vec4 fragColour;\n"
 	"uniform sampler2D texID;\n"
 	"\n"
 	"void main(void)\n"
 	"{\n"
-		"fragColour = texture(texID, srcCoordinatesVarying) * vec4(1.0, 1.0, 1.0, sin(offsetVarying));\n"	// vec4(1.0, 1.0, 1.0, 0.5)
+		"fragColour = texture(texID, srcCoordinatesVarying) * vec4(1.0, 1.0, 1.0, sin(lateralVarying));\n"
 	"}\n";
 
 #if defined(DEBUG)
diff --git a/Outputs/CRT.cpp b/Outputs/CRT.cpp
index 9fd57c530..849c4d2ed 100644
--- a/Outputs/CRT.cpp
+++ b/Outputs/CRT.cpp
@@ -58,7 +58,7 @@ void CRT::set_new_timing(int cycles_per_line, int height_of_display)
 
 	// width should be 1.0 / _height_of_display, rotated to match the direction
 	float angle = atan2f(scanSpeedYfl, scanSpeedXfl);
-	float halfLineWidth = (float)_height_of_display * 1.2f;
+	float halfLineWidth = (float)_height_of_display * 1.0f;
 	_widths[0][0] = (sinf(angle) / halfLineWidth) * kCRTFixedPointRange;
 	_widths[0][1] = (cosf(angle) / halfLineWidth) * kCRTFixedPointRange;
 }
@@ -222,8 +222,11 @@ void CRT::advance_cycles(int number_of_cycles, bool hsync_requested, const bool
 			position_y(1) = (kCRTFixedPointOffset + _rasterPosition.y - width[1]) >> 16;
 
 			tex_x(0) = tex_x(1) = tex_x(4) = tex_x;
-			tex_y(0) = tex_y(4) = tex_y;
-			tex_y(1) = tex_y + 1;
+
+			// these things are constants across the line so just throw them out now
+			tex_y(0) = tex_y(4) = tex_y(1) = tex_y(2) = tex_y(3) = tex_y(5) = tex_y;
+			lateral(0) = lateral(4) = lateral(5) = 0;
+			lateral(1) = lateral(2) = lateral(3) = 1;
 		}
 
 		// advance the raster position as dictated by current sync status
@@ -250,8 +253,6 @@ void CRT::advance_cycles(int number_of_cycles, bool hsync_requested, const bool
 
 			// if this is a data or level run then store the end point
 			tex_x(2) = tex_x(3) = tex_x(5) = tex_x;
-			tex_y(2) = tex_y(3) = tex_y+1;
-			tex_y(5) = tex_y;
 		}
 
 		// decrement the number of cycles left to run for and increment the