Update README.md

Author: banderlog

README.md

@@ -110,6 +110,8 @@ sudo apt-get update
 sudo apt install build-essential cmake git pkg-config python3-dev nasm python3 virtualenv libusb-1.0-0-dev chrpath patchelf
 ```
 
+**NB:** you will need ~6GB RAM and ~7GB disk space
+
 ### Preparing
 
 0. `git clone https://github.com/banderlog/opencv-python-inference-engine`