diff --git a/README-mpi-hints.md b/README-mpi-hints.md
index eef9967638fdb336d4402c87d2d141f6cc9f7883..94c3948c3ef48f4c5bfb94d659030a30f0ca5c8a 100644
--- a/README-mpi-hints.md
+++ b/README-mpi-hints.md
@@ -35,3 +35,16 @@ using the asynchronous progression settings:
 
 ## OpenMPI
 
+_Open MPI_ comes in many flavours with many combinations of underlying
+transport libraries and running on many different fabrics. A complete
+description of all combinations is beyond the scope of this guide.
+
+On Mellanox hardware, we have had success running version 4.0 with the
+UCX layer version 1.6 and using the following settings:
+
+```
+-mca coll_hcoll_enable 0
+UCX_TLS=ud_x,shm,self
+UCX_RC_MLX5_TM_ENABLE=n
+UCX_DC_MLX5_TM_ENABLE=n
+```