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amounts to essentially a two-way trip over the interface (from the drive to the PC and back to the
drive). I used two commands ( COPY and XCOPY ), running each one four times consecutively,
discarding the results of the first run and averaging the other three.
Note
To measure the time it took for each file copy, I used the TimeIt utility, which is a command-
line tool that records the time a specified command takes to run. TimeIt.exe is included with
the Windows Server 2003 Resource Kit Tools, which you can download from Microsoft
( http://go.microsoft.com/fwlink/?LinkId=4544 ). Note that TimeIt won't run on 64-bit versions
of Windows; in that case I would use “Measure-Command” in the Windows PowerShell
(included with Windows 7 and 8).
The average times to copy the file using the faster desktop system are shown in Table 14.8 .
Table 14.8. Elapsed Time to Copy a 300MB File on a 3.6GHz Desktop PC
As you can see from the results, when the faster desktop system was used, copying the file was from
nearly 13% (using COPY ) to 25% (using XCOPY ) faster over USB than it was over FireWire. Also,
it is interesting to note that using the XCOPY command was 49% faster than COPY over FireWire and
65% faster than COPY over USB.
The average times to copy the file using the slower laptop system are shown in Table 14.9 .
Table 14.9. Elapsed Time to Copy a 300MB File on a 1.7GHz Laptop PC
As you can see from the results, when the slower laptop system was used, copying the file was from
22% (using XCOPY ) to 26% (using COPY ) faster over FireWire than it was over USB. Also note that
using the XCOPY command was 52% faster than COPY over FireWire and 57% faster than COPY
over USB.
So which is faster in the “real world”? In this example, when copying the file on the higher-
performance desktop PC, USB 2.0 was faster; however, on the slower laptop PC, FireWire was
faster. But that's not all; I noticed another interesting detail: It seems that the relative speed and
performance of the PC had a large effect on the throughput of the USB 2.0 transfers, whereas it had
virtually no effect on the FireWire 400 transfers. Table 14.10 shows a comparison.
Table 14.10. USB/FireWire File Copy Performance: 3.6GHz Pentium 4 Desktop Versus a
1.7GHz Pentium M Laptop
 
 
 
 
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