diff --git a/conan-profiles/conan-profile-macOS-X64 b/conan-profiles/conan-profile-macOS-X64
index 7f5d34ef..514eceaa 100644
--- a/conan-profiles/conan-profile-macOS-X64
+++ b/conan-profiles/conan-profile-macOS-X64
@@ -17,7 +17,7 @@ embree3/*:avx512=True
 embree3/*:shared=True
 
 [conf]
-&:tools.build:cxxflags=["-march=x86-64"]
+&:tools.build:cxxflags=["-msse", "-msse2", "-msse3", "-msse4_1", "-msse4_2", "-mssse3", "-mavx", "-mfma"]
 
 [buildenv]
 CXX=clang++
diff --git a/doc/notes.md b/doc/notes.md
index b43caa01..838bc083 100644
--- a/doc/notes.md
+++ b/doc/notes.md
@@ -91,7 +91,7 @@ author).
 tried to have it minimal and it's 10.13. For the delocation to succeed, we also
 have to set `MACOSX_DEPLOYMENT_TARGET` environment variable to 10.13.
 
-
-
-we 
-
+## Vectorization
+For Intel, we stick to x86-64-v3 (Haswell, 2013), no more.
+MacOS Intel runner is not standard, so we start from a x86-64-v1 basis and we add
+extensions. Otherwise pyluxcore.so cannot be tested ("Illegal instruction").