diff --git a/plugins/GSdx/GSRendererDX.cpp b/plugins/GSdx/GSRendererDX.cpp
index 9fb0f4aaf0..c137dd226b 100644
--- a/plugins/GSdx/GSRendererDX.cpp
+++ b/plugins/GSdx/GSRendererDX.cpp
@@ -252,26 +252,12 @@ void GSRendererDX::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sourc
 	}
 
 	if(context->TEST.ATE)
-	{
 		ps_sel.atst = context->TEST.ATST;
-
-		switch(ps_sel.atst)
-		{
-		case ATST_LESS:
-			ps_cb.FogColor_AREF.a = (float)((int)context->TEST.AREF - 1);
-			break;
-		case ATST_GREATER:
-			ps_cb.FogColor_AREF.a = (float)((int)context->TEST.AREF + 1);
-			break;
-		default:
-			ps_cb.FogColor_AREF.a = (float)(int)context->TEST.AREF;
-			break;
-		}
-	}
 	else
-	{
 		ps_sel.atst = ATST_ALWAYS;
-	}
+
+	if (context->TEST.ATE && context->TEST.ATST > 1)
+		ps_cb.FogColor_AREF.a = (float)context->TEST.AREF;
 
 	if(tex)
 	{
@@ -376,19 +362,6 @@ void GSRendererDX::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sourc
 
 		ps_sel.atst = iatst[ps_sel.atst];
 
-		switch(ps_sel.atst)
-		{
-		case ATST_LESS:
-			ps_cb.FogColor_AREF.a = (float)((int)context->TEST.AREF - 1);
-			break;
-		case ATST_GREATER:
-			ps_cb.FogColor_AREF.a = (float)((int)context->TEST.AREF + 1);
-			break;
-		default:
-			ps_cb.FogColor_AREF.a = (float)(int)context->TEST.AREF;
-			break;
-		}
-
 		dev->SetupPS(ps_sel, &ps_cb, ps_ssel);
 
 		bool z = om_dssel.zwe;
diff --git a/plugins/GSdx/res/tfx.fx b/plugins/GSdx/res/tfx.fx
index 013080a810..cdd9ec4c47 100644
--- a/plugins/GSdx/res/tfx.fx
+++ b/plugins/GSdx/res/tfx.fx
@@ -519,19 +519,24 @@ void atst(float4 c)
 	else if(PS_ATST == 2) // l
 	{
 		#if PS_SPRITEHACK == 0
-		clip(AREF - a);
+		clip(AREF - a - 0.5f);
 		#endif				
 	}
 	else if(PS_ATST == 3) // le
 	{
-		clip(AREF - a);
+		clip(AREF - a + 0.5f);
 	}
 	else if(PS_ATST == 4) // e
 	{
-		clip(0.5f - abs(a - AREF));	}
-	else if(PS_ATST == 5 || PS_ATST == 6) // ge, g
+		clip(0.5f - abs(a - AREF));
+	}
+	else if(PS_ATST == 5) // ge
 	{
-		clip(a - AREF);
+		clip(a - AREF + 0.5f);
+	}
+	else if(PS_ATST == 6) // g
+	{
+		clip(a - AREF - 0.5f);
 	}
 	else if(PS_ATST == 7) // ne
 	{