Start Regedit.

Navigate to
HKEY_CURRENT_USER\Control Panel\Desktop
Select MenuShowDelay from the list on the right.
Right on it and select Modify.
Change the value to 0.
Reboot your computer.
(Note : If you have other accounts you might also go to
HKEY_USERS/.DEFAULT/Control Panel/Desktop
and do the same thing.)
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Speed up Diskcache
Open Regedit
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session ManagerMemory Management\IoPageLockLimit

Modify the value in Hex depending on the size of your RAM
RAM modified value(Hex)
64M 1000
128M 4000
256M 10000
512M or more 40000