More on ATA vs. SCSI

Jim Whitehead (
Thu, 03 Sep 1998 13:52:25 -0700

Here is some further information on the ATA vs. SCSI debate:

This article compares the same disk drive, the Quantum Fireball SE, a
6.4Gig disk with a rotational speed of 5400 RPM, 128K buffer (on the low
side these days), with a seek time of 9.5ms, in both Ultra-ATA and
Ultra-SCSI configurations. The article runs the Ziff-Davis Winbench98
and the Adaptec ThreadMark 2.0 test suites. In both cases, the throughput
of the Ultra-ATA model was greater than the Ultra-SCSI by about 13-15%.
Though CPU utilization for the Ultra-SCSI was lower in both suites, the
CPU utilization per megabyte transferred was lower for the Ultra-ATA.

This indicates to me that for applications running on a computer with
a single disk drive, which have heavy disk access but low to medium
CPU usage, the Ultra-ATA interface will offer better performance.
But, since processing power is zero-sum, in high-CPU utilization
applications, the Ultra-SCSI interface is better, sacrificing some
disk performance for greater processor utilization.

Of course the caveat is that this is a comparison of single-disk
systems. For computers which have multiple disk drives per computer,
the Ultra-SCSI interface will offer far better performance than

Also, the site that hosts this article,, at:

Offers a pretty staggering array of articles and comparisons of storage

- Jim