diff --git a/README.md b/README.md
index 268f512..788df8e 100644
--- a/README.md
+++ b/README.md
@@ -161,6 +161,7 @@ optional arguments:
   -v, --version         show program's version number and exit
 ```
 
+**Note**: RiboDetector uses multiprocessing with shared memory, thus the memory use of a single process indicated in `htop` or `top` is actually the total memory used by RiboDector. Some job submission system like SGE mis-calculated the total memory use by adding up the memory use of all process. If you see this do not worry it will cause out of memory issue. 
 
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