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View Full Version : Speed Comparisons?


SteveL
03-18-2007, 12:19 AM
Hi,

Has anyone done testing to compare the length of time that it takes to SMART UPDATE onto various targets, e.g., FireWire 400 vs. 800 vs. USB?

Does the speed of the FireWire disk and type of FireWire make any difference?

What is the limiting bottleneck in a SMART UPDATE? The speed of the source disk? processor speed? or target disk?

Thanks,
-steve.

dnanian
03-18-2007, 12:22 AM
The limiting bottleneck is the speed of the I/O system. But I don't think you're likely to see a huge difference between a FW400 and FW800 drive...

SteveL
03-18-2007, 05:43 PM
Hey thanks Dave. My personal experience is so varied that I'm at a loss to offer much of an opinion.

Other's real observations would be welcomed.

klmorin
03-18-2007, 09:36 PM
Exact. But, in fact, we must consider two things: analysis of the data and the transfer of the data.

It is clear that the analysis does not depend at all on the type of connection (at least for the source). But, it's different for the transfer of data.

On my system, a smartupdate backup takes about one minute for one Gb, with either connection (FireWire or USB), if no data were added or modified. On the other hand, if data must be transferred, the process is two or three times faster in FireWire. But many factors may influence the performance.

sdsl
03-19-2007, 05:20 PM
For what it's worth, I have done smart backups with firewire 400 and 800 for a 50-GB data set. The smart backup update takes about 9 minutes over firewire 400 and about 6 minutes over firewire 800. For the original full backup with erase of target drive, the two backups were about 90 minutes and 70 minutes -- but there may be other factors since the firewire 800 is done with a Maxtor 500 GB drive which is a faster drive than the Firelite Smartdisk used for the firewire 400 backups. Overall, I believe the firewire 800 is faster but in practice, unless one is backing up a few very large files, I doubt much of a difference would be observed.

matt!
07-19-2007, 05:46 AM
Backing up my 160GB internal drive to my new external drive I am getting roughly twice the throughput using Firewire 800 (WD MyBook Pro, >8MB/s) compared to my old USB2 external drive (WD MyBook Essential, ~4MB/s).

I am using an aging PowerMac 1.8 G5.

matt

dnanian
07-19-2007, 09:01 AM
Oh, definitely not a surprise -- USB drives, even hi-speed ones, aren't very fast doing this kind of thing.