Navigate to HKLM\System\CurrentControlSet\Services\NTFS\EFS\Parameters and set the parameter of EFSKCACHEPERIOD to a value between 2 and 30. default is 5. Value suggest the time in seconds the kernel will cache the session key for a user for a given file. The Kernel will not validate the user credentials during this cache period. This has the net effect of faster access to encrypted files that may be opened several times during a given time period.This is helpful in kernel and user mode of the EFS (encrypting file system) as it provides quicker access to frequently use components. Similarly navigate to HKLM\Software\Microsoft\Windows NT\CurrentVersion\EFS and set the value of KeyCacheValidationPeriod to a value in units of second from 1 minute to 1 day (60 to 86400).
Microsoft has an interesting article on this at Registry Keys Used to Tune EFS Caching (Q278256). Read
it for complete details.