diff --git a/src/nodebuild.h b/src/nodebuild.h
index 81c7b1345..ce68c4682 100644
--- a/src/nodebuild.h
+++ b/src/nodebuild.h
@@ -347,7 +347,7 @@ inline int FNodeBuilder::ClassifyLine (node_t &node, const FPrivVert *v1, const
 #ifdef DISABLE_SSE
 	return ClassifyLine2 (node, v1, v2, sidev);
 #else
-#if defined(__SSE2__) || defined(_M_IX64)
+#if defined(__SSE2__) || defined(_M_X64)
 	// If compiling with SSE2 support everywhere, just use the SSE2 version.
 	return ClassifyLineSSE2 (node, v1, v2, sidev);
 #elif defined(_MSC_VER) && _MSC_VER < 1300
diff --git a/src/x86.cpp b/src/x86.cpp
index ec36aae93..89d88333d 100644
--- a/src/x86.cpp
+++ b/src/x86.cpp
@@ -299,7 +299,7 @@ void DoBlending_SSE2(const PalEntry *from, PalEntry *to, int count, int r, int g
 	}
 #endif
 
-#if defined(__amd64__) || defined(_M_IX64)
+#if defined(__amd64__) || defined(_M_X64)
 	long long color;
 
 	blending256 = _mm_set_epi64x(0x10001000100ll, 0x10001000100ll);