NCQ (Native Command Queuing) and TCQ (Tagged Command Queuing) Explained
Performance
Contents
We made some basic benchmarking using a NCQ-capable Serial ATA hard disk drive (Seagate ST3160023AS, 160 GB) with PC using the following configuration: 3.2 GHz Pentium 4, 1 GB RAM, GeForce 6800 VGA and Intel motherboard. We ran two programs, PCMark04 and IOMeter, with NCQ disabled and then enabled.
The results achieved with PCMark04 were the following: HDD Usage increased from 5,978 MB/s to 6,112 MB/s, an increase of only 2.24%. Windows XP loading time performance (XP startup) improved 9.76%, jumping from 8,947 MB/s to 9,821 MB/s.
The hard disk performance with IOMeter with NCQ disabled was 119 (a proprietary unit), jumping to 142 when we enabled NCQ, a 19.32% performance improvement. Not bad at all.
The performance difference between IOMeter and PCMark04 is easily explained. NCQ feature only improves the hard disk drive performance when it receives a series of out-of-order commands. It was very likeable that PCMark04 hard disk performance benchmarking used a series of sequential – i.e., in-order – commands, while IOMeter used a random workload, hence the better results on this program. Notice how Windows XP loading time – which loads files stored in several different positions of the hard drive – measured by PCMark04 improved considerably.
