Speed of USB 2

  • Thread starter Thread starter Pat
  • Start date Start date
P

Pat

Hi All,

Just a quick blob of info please. I'm sure that you all know the answer
and that it's posted all over the place, but please make it simple for me!
How long should it take to copy a half Gig file from one HD (external) to
another (internal)
via a USB 2 connection?
Should the speed be about the same both ways?

Thank you

Pat
 
Pat said:
Hi All,

Just a quick blob of info please. I'm sure that you all know the answer
and that it's posted all over the place, but please make it simple for me!
How long should it take to copy a half Gig file from one HD (external) to
another (internal)
via a USB 2 connection?
Should the speed be about the same both ways?
Click to expand...

USB2 is 480kbs max, but that is shared across all connected devices. Also,
the read and write times depend on what the drives are doing. A copy from a
source drive that also contains an overtaxed swap file, to a drive that is
being indexed, would take lots longer than if neither drive had any activity
going on. And doing the copy while a USB camera is downloading to a
different drive will slow it as well. Not to mention the fact that USB puts
lots of load on the CPU, so doing a copy while the CPU s also trying to do
something else will be slower.

Not much use, am I? Sorry. Maybe someone has a more concrete answer for you.

Gordon
 
Gordon said:
USB2 is 480kbs max, but that is shared across all connected devices. Also,
the read and write times depend on what the drives are doing. A copy from a
source drive that also contains an overtaxed swap file, to a drive that is
being indexed, would take lots longer than if neither drive had any activity
going on. And doing the copy while a USB camera is downloading to a
different drive will slow it as well. Not to mention the fact that USB puts
lots of load on the CPU, so doing a copy while the CPU s also trying to do
something else will be slower.

Not much use, am I? Sorry. Maybe someone has a more concrete answer for you.

Gordon
Click to expand...

Actually, USB 2 is 480 Mbps max, not Kbps. You are correct though that
there are many variables involved in copying files from/to external or
internal devices. For instance, the need for your antivirus software to
scan the file before allowing it to be written will slow things down, as
well as any limitations or bottlenecks in the hardware and whatever else
is running at the same time on the PC.


--
The reader should exercise normal caution and backup the Registry and
data files regularly, and especially before making any changes to their
PC, as well as performing regular virus and spyware scans. I am not
liable for problems or mishaps that occur from the reader using advice
posted here. No warranty, express or implied, is given with the posting
of this message.
 
Not much use, am I? Sorry. Maybe someone has a more concrete >answer for
Click to expand...
you.

In case Pat is just interested in a very rough ballpark figure, I just
copied 497MB (about 6 or 8 files) from my external to my internal, and it
took ~40 sec.

Big caveat: I have a firewire connection, not USB2 (the computer I ran this
test on only has USB1). But they're comparable, aren't they? I could run
this test later on a USB2 system.

I wasn't doing much of anything else while the copy took place.
 
ggull said:
Big caveat: I have a firewire connection, not USB2 (the computer I ran
this
test on only has USB1). But they're comparable, aren't they? I could run
this test later on a USB2 system.
Click to expand...

Firewire is much superior to USB in that the Firewire chip passes less off
to the CPU. Even at a max of 400Mbs, Firewire is usually faster than 480Mbs
USB2 in the real world. Pro audio external drives and high end recording
gear are all Firewire for this reason, tho you can get some entry level 2
channel recording gear in USB.

Best,
Gordon
 
null said:
Actually, USB 2 is 480 Mbps max, not Kbps.
Click to expand...

Good call! Too much lately dealing with modems and internet connections. I
just put a K in front of that bs automatically.

Gordon
 
Gordon Price said:
Firewire is much superior to USB in that the Firewire chip passes less off
to the CPU. Even at a max of 400Mbs, Firewire is usually faster than 480Mbs
USB2 in the real world. Pro audio external drives and high end recording
gear are all Firewire for this reason, tho you can get some entry level 2
channel recording gear in USB.
Click to expand...

OK, I finally ran the same test on my new computer with USB2:

497 MB, 6 Files

1) Firewire, external drive to ~4 year old computer (Win Me, Athlon (~1GHz?
I've lost track of whatever I look under to find the processor speed),
vanilla HD). Time, ~40 sec.

2) USB 2, external to new computer, (Win XP HE, 3GHz P4, vanilla SATA
drive). Time ~20 sec.

3) just for fun, copy (not move) from one directory to another on same
internal SATA drive. Time just a bit less, maybe 17 sec.

In all cases, computer basically idle, no other USB/Firewire devices plugged
in.
Timing is crude, using wrist watch.

I'm not sure why the Firewire test was that much slower than the USB2.
Maybe just a slower-everything recipient computer. Maybe the HD was pretty
full (though recently defragged) on the old computer, and pretty empty on
the new.
 
ggull said:
OK, I finally ran the same test on my new computer with USB2:

497 MB, 6 Files

1) Firewire, external drive to ~4 year old computer (Win Me, Athlon
(~1GHz?
I've lost track of whatever I look under to find the processor speed),
vanilla HD). Time, ~40 sec.

2) USB 2, external to new computer, (Win XP HE, 3GHz P4, vanilla SATA
drive). Time ~20 sec.

3) just for fun, copy (not move) from one directory to another on same
internal SATA drive. Time just a bit less, maybe 17 sec.

In all cases, computer basically idle, no other USB/Firewire devices
plugged
in.
Timing is crude, using wrist watch.

I'm not sure why the Firewire test was that much slower than the USB2.
Maybe just a slower-everything recipient computer. Maybe the HD was
pretty
full (though recently defragged) on the old computer, and pretty empty on
the new.
Click to expand...

Interesting. I certainly would have expected something close to parity, with
the Firewire maybe a little behind in this case. Firewire really shines when
the computer is also doing other work, as the Firewire chip doesn't expect
the CPU to help out. Not a big deal for simple transfers, but for audio
recording, where the CPU is processing the signal before it goes to the HD,
this can be huge. It is also an issue when using an external drive for
backup. You don't want your server bogging down when you need to recover a
bunch of files in the middle of the day.
I did learn something a few days ago regarding Firewire. The chip for
Firewire400 basically sucks, and most musicians and studios will use a
Firewire800 device in a Firewire400 port, just because the new chip is so
much better. One guy I talked to lost an entire live set because he used a
Firewire400 drive. Never a problem with Firewire800.

Best,
Gordon
 
Thank you!

That was the sort of information that I was looking for. I expected that
doing other things could seriously affect the speed.
I am interested in the comments re firewire and would like to hear your
result. I suspect that firewire will be noticably faster in the real world.

I have added a Firewire / USB card to my PC and have a feeling that the USB
is not working to speed.
I don't have any firewire devices at present - 'Future Proofing'!!

I hope that you will post a comparson.

TIA

Pat
 
ggull said:
When did Firewire 400 transition to 800? As I said, the computer (and the
ports on it) are probably ~4 years old and could have the lower standard.
The external drive is a year or less.
Click to expand...

Maybe a year or two. At four years old, the machine is certainly 400, and
unless you knowingly paid extra, the device probably is too. From what I
have seen, it is only in the last few months that Firewire800 devices don't
cost a fair premium over 400 devices.

Gordon
 
Gordon Price said:
Maybe a year or two. At four years old, the machine is certainly 400, and
unless you knowingly paid extra, the device probably is too.
Click to expand...
Given that it was a USB/Firewire combo, and on sale, and didn't say anything
explicitly about "new, improved" Firewire or Fw800, I'd bet you're right.
Still, plenty good enough for my purposes. And my experiment on the USB2
enabled computer should have answered the OP's question. (Though I'd be
curious why he asked, if Pat cared to check back in.)
 
Back
Top