diff --git a/idlib/math/Simd_AltiVec.cpp b/idlib/math/Simd_AltiVec.cpp
index eb3a70b..4b894f3 100644
--- a/idlib/math/Simd_AltiVec.cpp
+++ b/idlib/math/Simd_AltiVec.cpp
@@ -47,7 +47,7 @@ If you have questions concerning this license or the applicable additional terms
 //
 //===============================================================
 
-#if defined(MACOS_X) && defined(__ppc__)
+#if defined(__GNUC__) && defined(__ALTIVEC__)
 
 #ifdef PPC_INTRINSICS
 	// for square root estimate instruction
diff --git a/idlib/math/Simd_AltiVec.h b/idlib/math/Simd_AltiVec.h
index e7bdac3..351ca6c 100644
--- a/idlib/math/Simd_AltiVec.h
+++ b/idlib/math/Simd_AltiVec.h
@@ -106,7 +106,7 @@ If you have questions concerning this license or the applicable additional terms
 //#define DRAWVERT_PADDED
 
 class idSIMD_AltiVec : public idSIMD_Generic {
-#if defined(MACOS_X) && defined(__ppc__)
+#if defined(__GNUC__) && defined(__ALTIVEC__)
 public:
 
 	virtual const char * VPCALL GetName( void ) const;
diff --git a/idlib/math/Simd_MMX.cpp b/idlib/math/Simd_MMX.cpp
index ea02ae8..37bb917 100644
--- a/idlib/math/Simd_MMX.cpp
+++ b/idlib/math/Simd_MMX.cpp
@@ -39,7 +39,7 @@ If you have questions concerning this license or the applicable additional terms
 //
 //===============================================================
 
-#if defined(MACOS_X) && defined(__i386__)
+#if defined(__GNUC__) && defined(__MMX__)
 /*
 ============
 idSIMD_MMX::GetName
diff --git a/idlib/math/Simd_MMX.h b/idlib/math/Simd_MMX.h
index a9c23f5..83fce24 100644
--- a/idlib/math/Simd_MMX.h
+++ b/idlib/math/Simd_MMX.h
@@ -39,7 +39,7 @@ If you have questions concerning this license or the applicable additional terms
 
 class idSIMD_MMX : public idSIMD_Generic {
 public:
-#if defined(MACOS_X) && defined(__i386__)
+#if defined(__GNUC__) && defined(__MMX__)
 	virtual const char * VPCALL GetName( void ) const;
 
 #elif defined(_WIN32)
diff --git a/idlib/math/Simd_SSE.cpp b/idlib/math/Simd_SSE.cpp
index 4c5917c..a4de610 100644
--- a/idlib/math/Simd_SSE.cpp
+++ b/idlib/math/Simd_SSE.cpp
@@ -48,7 +48,7 @@ If you have questions concerning this license or the applicable additional terms
 #define DRAWVERT_TANGENT1_OFFSET	(ptrdiff_t(src) - ptrdiff_t(&src->tangents[1]))
 #define DRAWVERT_COLOR_OFFSET		(ptrdiff_t(src) - ptrdiff_t(&src->color))
 
-#if defined(MACOS_X) && defined(__i386__)
+#if defined(__GNUC__) && defined(__SSE__)
 
 #include <xmmintrin.h>
 
diff --git a/idlib/math/Simd_SSE.h b/idlib/math/Simd_SSE.h
index f505444..906f861 100644
--- a/idlib/math/Simd_SSE.h
+++ b/idlib/math/Simd_SSE.h
@@ -39,7 +39,7 @@ If you have questions concerning this license or the applicable additional terms
 
 class idSIMD_SSE : public idSIMD_MMX {
 public:
-#if defined(MACOS_X) && defined(__i386__)
+#if defined(__GNUC__) && defined(__SSE__)
 	virtual const char * VPCALL GetName( void ) const;
 	virtual void VPCALL Dot( float *dst,			const idPlane &constant,const idDrawVert *src,	const int count );
 	virtual	void VPCALL MinMax( idVec3 &min,		idVec3 &max,			const idDrawVert *src,	const int *indexes,		const int count );
diff --git a/idlib/math/Simd_SSE2.cpp b/idlib/math/Simd_SSE2.cpp
index 639de48..be77876 100644
--- a/idlib/math/Simd_SSE2.cpp
+++ b/idlib/math/Simd_SSE2.cpp
@@ -40,9 +40,9 @@ If you have questions concerning this license or the applicable additional terms
 //	SSE2 implementation of idSIMDProcessor
 //
 //===============================================================
-#if defined(MACOS_X) && defined(__i386__)
+#if defined(__GNUC__) && defined(__SSE2__)
 
-#include <xmmintrin.h>
+#include <emmintrin.h>
 
 #define SHUFFLEPS( x, y, z, w )		(( (x) & 3 ) << 6 | ( (y) & 3 ) << 4 | ( (z) & 3 ) << 2 | ( (w) & 3 ))
 #define R_SHUFFLEPS( x, y, z, w )	(( (w) & 3 ) << 6 | ( (z) & 3 ) << 4 | ( (y) & 3 ) << 2 | ( (x) & 3 ))
diff --git a/idlib/math/Simd_SSE2.h b/idlib/math/Simd_SSE2.h
index 81863b8..407f846 100644
--- a/idlib/math/Simd_SSE2.h
+++ b/idlib/math/Simd_SSE2.h
@@ -39,7 +39,7 @@ If you have questions concerning this license or the applicable additional terms
 
 class idSIMD_SSE2 : public idSIMD_SSE {
 public:
-#if defined(MACOS_X) && defined(__i386__)
+#if defined(__GNUC__) && defined(__SSE2__)
 	virtual const char * VPCALL GetName( void ) const;
 	virtual void VPCALL CmpLT( byte *dst,			const byte bitNum,		const float *src0,		const float constant,	const int count );
 
diff --git a/idlib/math/Simd_SSE3.cpp b/idlib/math/Simd_SSE3.cpp
index 72bc062..e4d0ac8 100644
--- a/idlib/math/Simd_SSE3.cpp
+++ b/idlib/math/Simd_SSE3.cpp
@@ -42,7 +42,7 @@ If you have questions concerning this license or the applicable additional terms
 //
 //===============================================================
 
-#if defined(MACOS_X) && defined(__i386__)
+#if defined(__GNUC__) && defined(__SSE3__)
 
 /*
 ============
diff --git a/idlib/math/Simd_SSE3.h b/idlib/math/Simd_SSE3.h
index 83715f3..97183b6 100644
--- a/idlib/math/Simd_SSE3.h
+++ b/idlib/math/Simd_SSE3.h
@@ -39,7 +39,7 @@ If you have questions concerning this license or the applicable additional terms
 
 class idSIMD_SSE3 : public idSIMD_SSE2 {
 public:
-#if defined(MACOS_X) && defined(__i386__)
+#if defined(__GNUC__) && defined(__SSE3__)
 	virtual const char * VPCALL GetName( void ) const;
 
 #elif defined(_WIN32)