Enable FileSystem cache
 

Enable FileSystem cache:

To enable the FileSystem cache, speeding up overall performance at the risk of the cache not being written on a sudden reset:
HKLM\System\StorageManager\FATFS\EnableCache = 1 (DWORD decimal)
To disable again:
HKLM\System\StorageManager\FATFS\EnableCache = 0 (DWORD decimal)

Note that by default, the cache size is zero, and you will see no effect. See "Increase FileSystem cache" to incease the cache size