diff --git a/src/rendering/polyrenderer/poly_renderthread.cpp b/src/rendering/polyrenderer/poly_renderthread.cpp
index ccc8338bf..7e5c834ca 100644
--- a/src/rendering/polyrenderer/poly_renderthread.cpp
+++ b/src/rendering/polyrenderer/poly_renderthread.cpp
@@ -151,7 +151,7 @@ void PolyRenderThreads::RenderThreadSlices(int totalcount, std::function<void(Po
 
 	int numThreads = std::thread::hardware_concurrency();
 	if (numThreads == 0)
-		numThreads = 4;
+		numThreads = 1;
 
 	if (r_scene_multithreaded == 0 || r_multithreaded == 0)
 		numThreads = 1;
diff --git a/src/rendering/swrenderer/scene/r_scene.cpp b/src/rendering/swrenderer/scene/r_scene.cpp
index 32a1a47c9..8134e59a3 100644
--- a/src/rendering/swrenderer/scene/r_scene.cpp
+++ b/src/rendering/swrenderer/scene/r_scene.cpp
@@ -200,7 +200,16 @@ namespace swrenderer
 	{
 		int numThreads = std::thread::hardware_concurrency();
 		if (numThreads == 0)
-			numThreads = 4;
+		{
+			static bool firstCall = true;
+			if (firstCall)
+			{
+				firstCall = false;
+				Printf("Warning: Unable to determine number of CPU cores/threads for this computer. To improve performance, please type 'r_multithreaded x' in the console, where x is the number of threads to use.\n");
+			}
+
+			numThreads = 1;
+		}
 
 		if (r_scene_multithreaded == 0 || r_multithreaded == 0)
 			numThreads = 1;