What are the benefits of a SATA hard drive supporting NCQ? What applications benefit from it?
Native Command Queuing allows the disk to accept up to 32 commands and reorder those commands based on the most efficient access pattern. Meaning the disk will order the commands to minimize head movement. Most desktop applications do not see any real benefit from NCQ since desktop applications generally only have a small number of write/read commands outstanding at any given time. Applications that can benefit greatly from NCQ are applications that issue large number of asynchronous commands to the disk. These types of applications are generally used in servers. The best way to see the benefit of NCQ is to use a benchmark called IOMeter. With this benchmark you can setup scenarios in which many commands are issued simultaneously.