diff --git a/4_graphic_interface.md b/4_graphic_interface.md
index ff22703..c284d04 100644
--- a/4_graphic_interface.md
+++ b/4_graphic_interface.md
@@ -14,8 +14,24 @@ echo exec cinnamon-session >> ~/.xinitrc
 ```
 
 other gui tools
----
+---------------
 ```
 # for open archive in gui
 pacman -S cfile-roller
 ```
+
+Check the Cart graphic corectly install
+---------------------------------------
+```
+# list the output card : (permit to know wich graphic ard we have)
+lspci | grep VGA
+# install all the graphic card drivers:
+pacman -S xorg xorg-drivers
+# restart computer
+# ...
+# install bench tool
+pacman -S virtualgl
+# run sample:
+glxspheres64
+# here we will know how the graphic interfae is run
+```