SSD native command queuing (NCQ)

Last Updated on July 15, 2017 by Dave Farquhar

What is SSD native command queuing (NCQ)? Think of it as a technology to make SSDs more efficient.

Really expensive, high performance hard drives had NCQ for years. But it works even better in SSDs.

Computers usually don’t just send one request to a hard drive or SSD. They sent twelve. Or hundreds. NCQ allows the drive to reorder those requests. This cuts down on some of the randomness, which is a good thing. SSDs are bad at random I/O, and hard drives are incredibly bad at it.

With NCQ, the drive can do things in the fastest order it can think of, then return the data to the computer in the order it asked for it. This lets the drive operate at peak efficiency without the computer having to do anything special.

Since even the fastest SSD is usually the biggest bottleneck in a computer system, NCQ gives a nice performance boost.

Most current SSDs have NCQ, even inexpensive ones. But if you put an SSD in an older computer, you may not get the benefit of NCQ and/or TRIM. If your computer’s BIOS or UEFI has an AHCI mode for its SATA connections, you have to enable it in Windows (scroll to the end of the link) and then enable it in your BIOS or UEFI. Otherwise, NCQ sits dormant. The computer still benefits from the SSD’s fast seek times and transfer rates, but not as much as a newer computer would.

So when you upgrade to an SSD, double-check those BIOS settings. Most newer machines have it enabled by default, but some machines had it turned off for better compatibility with older operating systems.

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2 thoughts on “SSD native command queuing (NCQ)

  • November 29, 2017 at 5:38 am

    “and/or TRIM” already a mistake because TRIM works perfectly well in IDE mode on older pc 😉

    • December 1, 2017 at 9:52 pm

      Definitely depends on the PC and possibly the drive. On some older PCs it does, but not on others. I use them in old PCs anyway (I have been since 2009) but you don’t always get all the benefits with older PCs.

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