Native Command Queuing

The resulting high CPU overhead and negligible performance gain contributed to a lack of market acceptance for ATA TCQ.

NCQ's implementation is preferable because the drive has more accurate knowledge of its performance characteristics and is able to account for its rotational position.

[6] One review in 2010 found improvements on the order of 9% (on average) with NCQ enabled in a series of Windows multitasking tests.

[8] Since the algorithms used inside drives' firmware for NCQ dispatch ordering are generally not publicly known, this introduces another level of uncertainty for hardware/firmware performance.

A proposed workaround is for the operating system to artificially starve the NCQ queue sooner in order to satisfy low-latency applications in a timely manner.

[10] On some drives' firmware, such as the WD Raptor circa 2007, read-ahead is disabled when NCQ is enabled, resulting in slower sequential performance.

Assuming a correct hardware implementation, this feature allows data consistency to be guaranteed when the disk's on-board cache is used in conjunction with system calls like fsync.

NCQ allows the drive itself to determine the optimal order in which to retrieve outstanding requests. This may, as here, allow the drive to fulfill all requests in fewer rotations and thus less time.