2. Command queuing is meant to assist multi-user situations, not single-user setups. With the recent release of Intel's 9xx chipsets, pundits and enthusiasts everywhere have been proclaiming that command queuing is the next big thing for the desktop. Wrong.
As evidenced by the disparities between the FastTrak S150 TX4 and TX4200 (otherwise identical except for the latter's added TCQ functionality), command queuing introduces significant overhead that fails to pay for itself performance-wise in the highly-localized, lower-depth instances that even the heaviest single-user multitasking generates.
It is becoming clear, in fact, that the maturity and across-the-board implementation of TCQ in the SCSI world is one of the principal reasons why otherwise mechanically superior SCSI drives stumble when compared to ATA units.
Consider that out of the 24 combinations yielded from the four single-user access patterns, one-to-four drive RAID0 arrays, and RAID1/10 mirrored arrays presented above, the non-TCQ S150 TX4 comes out on top in every case by a large margin. TCQ is only meant for servers, much like the technology mentioned just below.
