diff --git a/Core/GameEngine/Include/Common/GameDefines.h b/Core/GameEngine/Include/Common/GameDefines.h
index 7a6f4be4d11..1c87cd72938 100644
--- a/Core/GameEngine/Include/Common/GameDefines.h
+++ b/Core/GameEngine/Include/Common/GameDefines.h
@@ -87,6 +87,17 @@
 #define PRESERVE_RETAIL_SCRIPTED_CAMERA (1) // Retain scripted camera behavior present in retail Generals 1.08 and Zero Hour 1.04
 #endif
 
+// Whether to preserve the 1.41x speed discrepancy between straight and diagonal movements of all objects.
+#ifndef PRESERVE_RETAIL_PHYSICS_FORWARD_SPEED
+#define PRESERVE_RETAIL_PHYSICS_FORWARD_SPEED (1)
+#endif
+
+// Whether to preserve the 1.41x speed discrepancy between straight and diagonal movements of all scripted objects.
+// This setting is very relevant for legacy missions and cinematic sequences.
+#ifndef PRESERVE_RETAIL_SCRIPTED_PHYSICS_FORWARD_SPEED
+#define PRESERVE_RETAIL_SCRIPTED_PHYSICS_FORWARD_SPEED (1)
+#endif
+
 #ifndef RETAIL_COMPATIBLE_CRC
 #define RETAIL_COMPATIBLE_CRC (1) // Game is expected to be CRC compatible with retail Generals 1.08, Zero Hour 1.04
 #endif
diff --git a/GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Update/PhysicsUpdate.cpp b/GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Update/PhysicsUpdate.cpp
index 78b256e5b88..8c9085a3e62 100644
--- a/GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Update/PhysicsUpdate.cpp
+++ b/GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Update/PhysicsUpdate.cpp
@@ -957,21 +957,39 @@ Real PhysicsBehavior::getVelocityMagnitude() const
 Real PhysicsBehavior::getForwardSpeed2D() const
 {
 	const Coord3D *dir = getObject()->getUnitDirectionVector2D();
-
 	Real vx = m_vel.x * dir->x;
 	Real vy = m_vel.y * dir->y;
-
 	Real dot = vx + vy;
 
-	Real speedSquared = vx*vx + vy*vy;
-//	DEBUG_ASSERTCRASH( speedSquared != 0, ("zero speedSquared will overflow sqrtf()!") );// lorenzen... sanity check
-
-	Real speed = (Real)sqrtf( speedSquared );
+#if RETAIL_COMPATIBLE_CRC || PRESERVE_RETAIL_PHYSICS_FORWARD_SPEED
 
+	Real speed = (Real)sqrtf( vx*vx + vy*vy );
 	if (dot >= 0.0f)
 		return speed;
-
 	return -speed;
+
+#else
+
+#if PRESERVE_RETAIL_SCRIPTED_PHYSICS_FORWARD_SPEED
+	if (const AIUpdateInterface *ai = getObject()->getAIUpdateInterface())
+	{
+		if (ai->getLastCommandSource() == CMD_FROM_SCRIPT)
+		{
+			Real speed = (Real)sqrtf( vx*vx + vy*vy );
+			if (dot >= 0.0f)
+				return speed;
+			return -speed;
+		}
+	}
+#endif
+
+	// Inverse scale len by (1 + sqrt(2)) / 2 to adjust to the average of the former min/max movement speed.
+	// The inverse looks intuitively wrong, but it is correct, because the value returned by this function is
+	// used to determine the additional velocity needed to reach the target speed.
+	constexpr const Real DiagonalCompensation = 1.0f / 1.20710678f;
+	return dot * DiagonalCompensation;
+
+#endif
 }
 
 //-------------------------------------------------------------------------------------------------
@@ -982,19 +1000,40 @@ Real PhysicsBehavior::getForwardSpeed2D() const
 Real PhysicsBehavior::getForwardSpeed3D() const
 {
 	Vector3 dir = getObject()->getTransformMatrix()->Get_X_Vector();
-
 	Real vx = m_vel.x * dir.X;
 	Real vy = m_vel.y * dir.Y;
 	Real vz = m_vel.z * dir.Z;
-
 	Real dot = vx + vy + vz;
 
-	Real speed = (Real)sqrtf( vx*vx + vy*vy + vz*vz );
+#if RETAIL_COMPATIBLE_CRC || PRESERVE_RETAIL_PHYSICS_FORWARD_SPEED
 
+	Real speed = (Real)sqrtf( vx*vx + vy*vy + vz*vz );
 	if (dot >= 0.0f)
 		return speed;
-
 	return -speed;
+
+#else
+
+#if PRESERVE_RETAIL_SCRIPTED_PHYSICS_FORWARD_SPEED
+	if (const AIUpdateInterface *ai = getObject()->getAIUpdateInterface())
+	{
+		if (ai->getLastCommandSource() == CMD_FROM_SCRIPT)
+		{
+			Real speed = (Real)sqrtf( vx*vx + vy*vy + vz*vz );
+			if (dot >= 0.0f)
+				return speed;
+			return -speed;
+		}
+	}
+#endif
+
+	// Inverse scale len by (1 + sqrt(3)) / 2 to adjust to the average of the former min/max movement speed.
+	// The inverse looks intuitively wrong, but it is correct, because the value returned by this function is
+	// used to determine the additional velocity needed to reach the target speed.
+	constexpr const Real DiagonalCompensation = 1.0f / 1.36602540f;
+	return dot * DiagonalCompensation;
+
+#endif
 }
 
 //-------------------------------------------------------------------------------------------------