If you use the computer that does not meet the recommended system requirements (CPU: Core i5 2.5Ghz or higher, Memory: 4G byte or higher), the speed of scanning or saving the scanned image decreases.
Hint:
If you select [Select later] from [Document type] in the [Paper] tab of the ScanSnap setup dialog box, scanning speed may be improved by selecting "Flat document" or "Double-page spread (Book/Magazine)".