The Start menu has a delay between different tiers of the menu hierarchy. To speed this, you can change the value to zero. This will allow the different tiers to appear instantly.

To change this, follow the next steps:

1. Open the Registry Editor click on the Start button on your taskbar, then click on Run and type "regedit" and click on OK to start the regedit utility.
    
2. Expand HKEY_CURRENT_USER/Control Panel/Desktop (see picture 1).
   
   If you have other accounts expand HKEY_USERS/DEFAULT/Control Panel/Desktop
   
   

   Picture 1

    
3. Select "MenuShowDelay" from the list on the right, select Modify and change the value to "0".
   
   
4. The modifications you made will be in effect after you reboot your PC.