A lazy-write file system, such as the FAT file system when running Windows NT, uses an intelligent cache-management strategy and provides a way to recover data (such as the Chkdsk program) if there is an error when writing to the disk. All data are accessed via the file cache. While the user searches folders or reads files, data to be written to disk accumulates in the file cache. If the same data are modified several times, all those modifications are captured in the file cache. The result is that the file system needs to write to disk only once to update the data.
NTFS is recoverable file system. It combines the speed of a lazy-write file system with virtually instant recovery.
The NTFS file system guarantees the consistency of the volume by using standard transaction logging and recovery techniques, although it doesn't guarantee the protection of user data. It includes a lazy-write technique plus a volume-recovery technique that takes typically only a second or two to insure the integrity of all NTFS volumes each time the computer is restarted.
The file cache is just an area of RAM that contains the data. When you write data to disk, Windows NT's lazy-write technique says that the data are written, when, in fact, they are still in RAM.
There can also be cache memory on the disk controller or on the disk itself. If you are running MS-DOS or Windows 3.1x, using the disk or controller cache can really help performance. Windows NT's use of the lazy-write technique improves performance to the point where you might not see much more improvement by using the cache on the disk or the controller.
This information should help you decide whether you want to enable the disk or controller cache: