diff --git a/FDTD/engine_multithread.cpp b/FDTD/engine_multithread.cpp
index 96273de..0bc3d68 100644
--- a/FDTD/engine_multithread.cpp
+++ b/FDTD/engine_multithread.cpp
@@ -251,6 +251,13 @@ void thread::operator()()
 	//std::cout << "thread::operator() Parameters: " << m_start << " " << m_stop << std::endl;
 	//DBG().cout() << "Thread " << m_threadID << " (" << boost::this_thread::get_id() << ") started." << endl;
 
+	// speed up the calculation of denormal floating point values (flush-to-zero)
+#ifndef SSE_CORRECT_DENORMALS
+	unsigned int oldMXCSR = _mm_getcsr(); //read the old MXCSR setting
+	unsigned int newMXCSR = oldMXCSR | 0x8040; // set DAZ and FZ bits
+	_mm_setcsr( newMXCSR ); //write the new MXCSR setting to the MXCSR
+#endif
+
 	while (!m_enginePtr->m_stopThreads)
 	{
 		// wait for start
diff --git a/FDTD/engine_sse.cpp b/FDTD/engine_sse.cpp
index b075a49..660e6d6 100644
--- a/FDTD/engine_sse.cpp
+++ b/FDTD/engine_sse.cpp
@@ -38,8 +38,8 @@ Engine_sse::Engine_sse(const Operator_sse* op) : Engine(op)
 
 	// speed up the calculation of denormal floating point values (flush-to-zero)
 #ifndef SSE_CORRECT_DENORMALS
-	int oldMXCSR = _mm_getcsr(); //read the old MXCSR setting
-	int newMXCSR = oldMXCSR | 0x8040; // set DAZ and FZ bits
+	unsigned int oldMXCSR = _mm_getcsr(); //read the old MXCSR setting
+	unsigned int newMXCSR = oldMXCSR | 0x8040; // set DAZ and FZ bits
 	_mm_setcsr( newMXCSR ); //write the new MXCSR setting to the MXCSR
 #endif
 }