.SFCACHE File Extension
File TypeReadyBoost Cache File
File format categories include Binary, Text, XML, and Zip. The format of this file type has not been determined.
What is a SFCACHE file?
Cache file used by Windows Vista and 7 that may be created on a flash memory device; adds additional memory that Windows may access as virtual RAM, which may help improve system performance.
ReadyBoost can be enabled by right-clicking the icon of a flash memory device and selecting "Properties." Then click the ReadyBoost tab and check "Use this device." This will create a temporary file named "ReadyBoost.sfcache" on the flash disk.