How to make Gnome menus Faster in Ubuntu
You need to Edit the file /home/your_user_name/.gtkrc-2.0 file
add the following line
gtk-menu-popup-delay = 100
gtk-menu-popup-delay = 0
100 for 100 ms
0 for 0 ms
Save and exit the file.
echo "gtk-menu-popup-delay = 0" >> ~/.gtkrc-2.0
Now you need to Log off and log back in.
You can also try to get the icons cached in memory at startup
echo "find /usr/share/pixmaps/ | xargs cat > /dev/null" >> ~/mystart
echo "find /usr/share/icons/Human/ | xargs cat > /dev/null" >> ~/mystart
chmod +x ~/mystart
Then add it as startup to gnome (System -> Settings -> Sessions -> Add, and write "~/mystart")