diff --git a/config/config_macos_gnu.sh b/config/config_macos_gnu.sh
index 9dd5d9dc..b9459e7b 100644
--- a/config/config_macos_gnu.sh
+++ b/config/config_macos_gnu.sh
@@ -14,7 +14,7 @@ export USE_SUDO=N
 export PKGDIR=pkg
 export LOGDIR=log
 export OVERWRITE=N
-export NTHREADS=8
+export NTHREADS=4
 export   MAKE_CHECK=N
 export MAKE_VERBOSE=Y
 export   MAKE_CLEAN=N
@@ -24,8 +24,12 @@ export WGET="wget -nv "
 
 #
 # gfortran-10 needs the following
-export STACK_FFLAGS="-fallow-argument-mismatch -fallow-invalid-boz"
+export STACK_FFLAGS="-fallow-argument-mismatch -fallow-invalid-boz -march=native "
+export STACK_CFLAGS="-march=native"
 export STACK_CXXFLAGS="-march=native"
+export STACK_mpi_FFLAGS="-fopenmp"
+export STACK_mpi_CFLAGS="-fopenmp"
+export STACK_mpi_CXXFLAGS="-fopenmp"
 
 BREW=$(brew --prefix)