diff --git a/Eigen/src/Core/arch/Default/Settings.h b/Eigen/src/Core/arch/Default/Settings.h
index 8118f9dc1..8127e5754 100644
--- a/Eigen/src/Core/arch/Default/Settings.h
+++ b/Eigen/src/Core/arch/Default/Settings.h
@@ -67,10 +67,7 @@
   * Currently it must be 8 or 16. Other values will fail.
   */
 #ifndef EIGEN_ARCH_DEFAULT_NUMBER_OF_REGISTERS
-#if (defined __i386__)
 #define EIGEN_ARCH_DEFAULT_NUMBER_OF_REGISTERS 8
-#else
-#define EIGEN_ARCH_DEFAULT_NUMBER_OF_REGISTERS 16
 #endif
 
 #endif
diff --git a/Eigen/src/Core/arch/SSE/PacketMath.h b/Eigen/src/Core/arch/SSE/PacketMath.h
index 8c441810c..a7206e77d 100644
--- a/Eigen/src/Core/arch/SSE/PacketMath.h
+++ b/Eigen/src/Core/arch/SSE/PacketMath.h
@@ -29,6 +29,10 @@
 #define EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD 8
 #endif
 
+#ifndef EIGEN_ARCH_DEFAULT_NUMBER_OF_REGISTERS
+#define EIGEN_ARCH_DEFAULT_NUMBER_OF_REGISTERS (2*sizeof(void*))
+#endif
+
 typedef __m128  Packet4f;
 typedef __m128i Packet4i;
 typedef __m128d Packet2d;