If you are using a Kofax card (and any scanner), you can specify the extent to which buffering is used. Normally you should choose 3 pages for maximum performance. Increasing the value above 3 may result in faster scanning, but the price is reduced control during the scanning process.
Advanced scanner settings: Kofax settings
System requirements and installation
Installing and Configuring Virtual ReScan (VRS) (Nothing happens when I click the link.)