diff --git a/MPI/gromacs/2020/variants b/MPI/gromacs/2020/variants
new file mode 100644
index 0000000..18995bc
--- /dev/null
+++ b/MPI/gromacs/2020/variants
@@ -0,0 +1,3 @@
+gromacs/2020_sp        unstable gcc/7.4.0 openmpi/3.1.5_merlin6 cuda/10.0.130 Python/3.7.4 b:cmake/3.14.0
+gromacs/2020.2_sp      unstable gcc/7.5.0 openmpi/3.1.6_slurm cuda/10.0.130 Python/3.7.4 b:cmake/3.15.5
+gromacs/2020.2_sp_gpu  unstable gcc/7.5.0 openmpi/4.0.4_slurm cuda/10.0.130 Python/3.7.4 b:cmake/3.15.5
diff --git a/MPI/gromacs/build b/MPI/gromacs/build
index ce115b5..057a64e 100755
--- a/MPI/gromacs/build
+++ b/MPI/gromacs/build
@@ -11,10 +11,6 @@ else
 fi
 
 pbuild::pre_configure() {
-  # For enabling GPU, set to 'yes'
-  local enable_gpu='yes'
-
-  echo here
   pbuild::add_configure_args "-DCMAKE_BUILD_TYPE=RELEASE"
   pbuild::add_configure_args "-DGMX_MPI=on"
 
@@ -24,11 +20,16 @@ pbuild::pre_configure() {
     pbuild::add_configure_args "-DGFMX_DOUBLE=off"
   fi
 
-  if [[ "${enable_gpu}" == 'yes' ]]; then
+  if pbuild::use_flag "gpu"; then
  	pbuild::add_configure_args "-DGMX_GPU=on"
   else
  	pbuild::add_configure_args "-DGMX_GPU=off"
   fi
-  # To remove: pbuild::add_configure_args "-DGMX_SIMD=SSE2"
+
+  # For GMX_SIMD the lowest instruction number you think might work on all nodes
+  #   |- Available numbers: http://manual.gromacs.org/documentation/2020/install-guide/index.html#simd-support
+  #   |- AVX_512 is only for newest Intel processors (Xeon Scalable Gold, Core i9, etc.)
+  #      AVX_512 will not work on old GPUs, this is why we chood AVX2_256 which are processors from 2013
+  pbuild::add_configure_args "-DGMX_SIMD=AVX2_256"
   pbuild::add_configure_args "-DGMX_BUILD_OWN_FFTW=on"
 }