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24 May 2008

USB2 Really Is Slower Than FireWire

Don't believe the hype

Who are these people who claim that USB2 is as fast as FireWire? I can't believe these people didn't go and just plain gave it a try. My ages old FW400 momobay box with a 2.5" 120Gig IDE drive beets the pulp out of the 2.5" 80Gig SATA (that came with my MacBook) hooked on USB2 with an A.C.Ryan adapter. Read on for my (totally unscientific etc. etc.) test...

The USB2 copy mostly kept in the 16-17MB/sec speed range, while the FireWire copy usually was more in the 21-22MB/sec area. Even more interesting was that the FW started to copy, went up to that speed and stayed there, while the USB2 jumped around a lot - looks to me like there's something not optimized.

To test this, I copied over the Video_TS folder of my PGP presentation from the internal drive to the external drive, using the shell and timing it with /usr/bin/time (and watching disk activity in the "Activity Monitor"):

% du -sh /Media/Movies/PGP\ Presentation
3.4G    /Media/Movies/PGP Presentation

% # USB2:
% /usr/bin/time cp -r /Media/Movies/PGP\ Presentation/ .
  201.97 real         0.02 user        12.00 sys

% # FireWire 400:
% /usr/bin/time cp -r /Media/Movies/PGP\ Presentation/ .
  155.06 real         0.01 user        11.60 sys

Oh, that's only 46 seconds difference on 3.4Gigs of data. When I mirrored the 80Gig drive to my new drive last night, I guess the difference would have played out to a bit more time. Also too bad I don't have FW800 to test.

Posted by betabug at 10:23 | Comments (6) | Trackbacks (0)
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Re: USB2 Really Is Slower Than FireWire

It is my understanding that USB is of variable speed, whereas FW is not. And that the USB maximum is near (equal?) to that of FW.

Posted by: adamo at May 25,2008 16:05
Re: USB2 Really Is Slower Than FireWire

Well, in theory USB2 maximum transfer speed is greater than FireWire 400 max transfer speed. Theory doesn't match my practical results though.

Posted by: betabug at May 25,2008 17:06
Re: USB2 Really Is Slower Than FireWire

Well. For me firewire has been "a bit" faster than USB. But this was until I discovered my new external drive from western digital.

Before: Usb 2.0 = 21MB/sec, FW400 = 23 MB/sec... The new, FW400 = 30MB/sec

When I have some time I'll post some numbers.

Posted by: graffic at May 26,2008 14:45
Re: USB2 Really Is Slower Than FireWire

yes, FW can transfer your pr0n way faster

Posted by: wiwi at May 26,2008 18:48
Re: USB2 Really Is Slower Than FireWire


I also got myself an A.C. Ryan a week or so ago and I have the same trouble. My 4 year old Lacie is cranking faster than the brand-new Seagate SATA-2 in the A.C. Ryan enclosure. I get 12MB/s write... sad.

The Lacie is hooked up via FireWire 400 to an Intel iMac and the A.C. Ryan to a dual G5 PowerMac. Neither machine is a slouch.

I am suspecting the USB to SATA bridge in it. I was thinking of returning it but I do not have the patience...

This is a damned enclosure I am talking about:

Posted by: aris at June 04,2008 15:40
Re: USB2 Really Is Slower Than FireWire

I doubt that it's the A.C.Ryan's fault - some people suspect USB2 in general, some people say it's Apple's USB2 drivers, but in any case any other USB2 enclosure will likely give you the same results.

Posted by: betabug at June 04,2008 15:52
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