Ziff Davis Winbench 98

Quantum Fireball SE (UltraATA)

Quantum Fireball SE (SCSI-2940U2W)

Business Disk WinMark 98 (KB/s)

1254

1110

SS/Database

1128

987

WP

1522

1338

Publishing

1144

1046

Browsers

1426

1234

Task Switching

1822

1618

High-End Disk WinMark 98 (KB/s)

3722

3226

AVS/Express 3.1

2306

2008

Frontpage 97

2920

2818

MicroStation 95

7032

6090

Photoshop 4.0

3038

2488

Premiere 4.2

6952

5918

PV-Wave 6.1

2720

2264

Visual C++ 5.0

8220

7160

Disk/Read Random Access (ms)

16.3

18.0

Disk/Read Transfer Rate (KB/s)

Beginning

11800

11200

End

7170

6800

Disk/Read CPU Utilization (%)

5.9

3.9

Transfer Rate (KB/s)

11758

7388

The ATA Fireball SE bests the SCSI version by 13% in the Business Disk WinMark 98 and by 15% in the High-End Disk WinMark. Curiously the results for the ATA drive were also substantially better in the low-level tests in addition to the Disk WinMarks. Both drives supposedly have the same seek time and the same rotational speed (and thus latency) yet the ATA Fireball posted a 16.3ms average access time to the SCSI version's 18.0ms. The Disk/Read Transfer rates of the SCSI Fireball also lagged behind its ATA counterpart.

CPU utilization per megabyte transferred for both drives are virtually identical. There's a common perception floating around that ATA's CPU utilization even with busmaster drivers does not approach that of busmastering SCSI. CPU utilization scores of ATA drives when using the busmaster drivers including with Windows 95 OEM Service Release 2 indicate otherwise, however. SCSI does not have an advantage here.

ATA drives and controllers, on the other hand, do not offer a key SCSI feature: Command Queuing. This feature allows multiple requests to "queue" and remain pending on the SCSI subsystem as opposed to ATA's serial approach where one request must be finished before another is started. This parallel execution allows SCSI to reorder the requests into a sequence that minimizes head/actuator seek motions. Simply put, SCSI's advanced features should result in less degradation in multitasking and multithreaded environments.

We decided to turn to Adaptec's ThreadMark 2.0 Benchmark. Adaptec offers the benchmark as a more reliable indicator of overall disk performance in multitasking environments. ThreadMark is difficult to run consistently, however. To obtain repeatable results, the test machine's use of virtual memory must be disabled. Storage Review's testbed has 64 megs of RAM, enough to run most applications well, but -not- enough to guarantee stability without any virtual memory. With virtual memory enabled, ThreadMark results varied wildly, sometimes displaying sample deviations of over 100%. Disabling virtual memory contained the sample deviations to a much more usable 1%. The average of five trials is presented here.

Index Adaptec Threadmark Results
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