diff --git a/data_from_portwine/scripts/runlib b/data_from_portwine/scripts/runlib
index 70a512c8..0829605f 100755
--- a/data_from_portwine/scripts/runlib
+++ b/data_from_portwine/scripts/runlib
@@ -171,6 +171,7 @@ start_portwine () {
 
     if [[ "${PW_PRIME_RENDER_OFFLOAD}" == 1 ]] ; then
         export __NV_PRIME_RENDER_OFFLOAD=1
+        export __VK_LAYER_NV_optimus=NVIDIA_only
         export __GLX_VENDOR_LIBRARY_NAME=nvidia
     fi