diff --git a/src/rendering/hwrenderer/scene/hw_drawinfo.cpp b/src/rendering/hwrenderer/scene/hw_drawinfo.cpp
index 0c3d31b16..8f3fdb1b8 100644
--- a/src/rendering/hwrenderer/scene/hw_drawinfo.cpp
+++ b/src/rendering/hwrenderer/scene/hw_drawinfo.cpp
@@ -453,15 +453,13 @@ void HWDrawInfo::RenderPVS(bool drawpsprites, FRenderState& state)
 		multithread = false;
 		uselevelmesh = true;
 
-		ClipWall.Clock();
+		Bsp.Clock();
 
+		ClipWall.Clock();
 		static HWVisibleSetThreads threads;
 		threads.FindPVS(this);
-
 		ClipWall.Unclock();
 
-		Bsp.Clock();
-
 		if (!gl_levelmesh) // Update sector heights for the non-levelmesh rendering of sectors
 		{
 			for (int sectorIndex : SeenSectors.Get())
@@ -830,14 +828,18 @@ void HWDrawInfo::RenderScene(FRenderState &state)
 
 void HWDrawInfo::DrawSeenSides(FRenderState& state, LevelMeshDrawType drawType, bool noFragmentShader)
 {
+	RenderWall.Clock();
 	for (int sideIndex : SeenSides.Get())
 		level.levelMesh->DrawSide(state, sideIndex, drawType, noFragmentShader);
+	RenderWall.Unclock();
 }
 
 void HWDrawInfo::DrawSeenFlats(FRenderState& state, LevelMeshDrawType drawType, bool noFragmentShader)
 {
+	RenderFlat.Clock();
 	for (int sectorIndex : SeenSectors.Get())
 		level.levelMesh->DrawSector(state, sectorIndex, drawType, noFragmentShader);
+	RenderFlat.Unclock();
 }
 
 //-----------------------------------------------------------------------------
diff --git a/src/rendering/hwrenderer/scene/hw_visibleset.cpp b/src/rendering/hwrenderer/scene/hw_visibleset.cpp
index 6e09fe17d..ef45da4f9 100644
--- a/src/rendering/hwrenderer/scene/hw_visibleset.cpp
+++ b/src/rendering/hwrenderer/scene/hw_visibleset.cpp
@@ -611,7 +611,7 @@ void HWVisibleSetThreads::WorkerMain(int sliceIndex)
 				bool isLeft = sliceIndex % 2 == 0;
 				int left = isLeft ? sliceIndex : sliceIndex - 1;
 				int right = isLeft ? sliceIndex + 1 : sliceIndex;
-				if ((isLeft && !WorkFlags[right]) || (!isLeft && !WorkFlags[left]))
+				if (right < SliceCount && ((isLeft && !WorkFlags[right]) || (!isLeft && !WorkFlags[left])))
 				{
 					// Other side is also done. Merge results.
 					lock.unlock();