Notes about the SFCACHE file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries, unused processes and other unfavourable system settings to identify slowdown issues.
The SFCACHE file type is primarily associated with 'Windows Vista' by Microsoft Corporation. ReadyBoost is Windows Vista feature that allows you to plug a USB flash memory device into a USB 2.0 port on a PC and use it as a cache or virtual memory. The advantage is that it is much faster to cache to the USB drive than caching to your hard disk, speeding up your system and enhancing overall performance. The USB device must be capable of 2.5MB/sec throughput for 4K random reads and 1.75MB/sec for random writes. Since this file is in active use it should never be disturbed or opened.