Add some notes.

docs/running-jobs.md

@@ -294,6 +294,13 @@ module load GCC ParaStationMPI
 srun ./hellompi
 ```
 
+:::warning
+
+Always use the same software stack (e.g. compiler, MPI) that was used to build the software to ensure compatibility and optimal performance. Different versions can cause errors or degrade performance.
+
+:::
+
+
 Remember to specify `gpu:4` `gres` for JUWELS Booster.
 
 Then save the script and submit it for execution with:

docs/using-gpus.md

@@ -126,6 +126,12 @@ srun: Job step aborted: Waiting up to 6 seconds for job step to finish.
 `sgoto` takes the job id as the first argument and the node number within the job as the second argument where the counting starts with 0.  
 `nvidia-smi` prints some useful information about available GPUs on a node, like temperature, memory usage, currently running processes and power consumption.
 
+:::note
+
+In the example above, `nvidia-smi` shows 0% utilisation because the GPUs are not being used. If GPUs were being used, the utilisation metrics displayed by `nvidia-smi` would be non-zero, reflecting the active use of GPU resources.
+
+:::
+
 ## GPU Affinity
 
 On systems with more than one GPU per node, a choice presents itself - which GPU should be visible to which application task(s)?