The default speed of the Start Menu is pretty slow, but you can fix that by editing a Registry Key. "click on Start/Run - type in 'regedit' - and then click OK".
Navigate thru the left hand column and navigate to the following key:
HKEY_CURRENT_USER \ Control Panel \ Desktop \ MenuShowDelay
By default, the value is 400. Change this to a smaller value, such as 0, to speed it up.
If this doesn't work for some reason, then you might try the following: Navigate to Display Properties then Appearance then Effects and turn off the option titled Show menu shadow. You will get much better overall performance.
tip>>>>
Those who are getting stuck and not seeing menushowdelay just click on desktop in the menu, you will then see another list on the right scroll down till to find menushowdelay, you then have to click this till the settings come up can't remember if its once or twice. A box will open with the speed at 400 this is where you change it and then click ok.