diff --git a/tests/README.md b/tests/README.md
index f7a85b51a0..a121ff1414 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -43,6 +43,7 @@ For each set up it also tests:
 5. simulated load from HPC signal.
 
 ## Running Coverage   
+Make sure to run coverage on a GPU machine with at least 2 GPUs and NVIDIA apex installed. 
 
 ```bash
 cd pytorch-lightning