Most people use the start menu to navigate through various functions and applications in the system. However, the menu item’s are displayed with a delay of 400ms usually. You can reduce this delay. It is one of the simplest tweaks you can make to improve your experience in Windows.
In the Registry Editor:
1. Go to HKEY_CURRENT_USER\Control Panel\desktop
2. Add a string value named MenuShowDelay if it doesn’t exist
3. Set it’s value with a smaller number (usually I would set it to 0), with a value specifying the number of miliseconds (400 is default, smaller numbers are faster).
4. Restart your machine