Disk Read / Write Speeds

[Gerry]

How do internal drive read / write speeds typically compare with those
of a USB external drive?

TIA



~~~~


Gerry
~~~~
FCA
Stourport, England
Enquire, plan and execute
~~~~~~~~~~~~~~~~~~~

 

[Shenan Stanley]

How do internal drive read / write speeds typically compare with
those of a USB external drive?

The drive(s) themselves (inside the box that makes them USB accessible) are
the same as the drive(s) you would buy to put inside your PC. So the
difference would be due to the interface (USB 1.1/2.0/etc), the drive the
manufacturer decided to put inside the box and your computer specs in some
ways.

 

[Gerry]

Shenan

Given that the drives are identical then an external USB set up will be
slower?

Why do many users install external drives when there is a spare internal
slot. At least that is my impression, perhaps mistaken, that this
commonly is the case.

--
Regards.

Gerry
~~~~
FCA
Stourport, England
Enquire, plan and execute
~~~~~~~~~~~~~~~~~~~

 

[Shenan Stanley]

How do internal drive read / write speeds typically compare with
those of a USB external drive?

The drive(s) themselves (inside the box that makes them USB
accessible) are the same as the drive(s) you would buy to put
inside your PC. So the difference would be due to the interface
(USB 1.1/2.0/etc), the drive the manufacturer decided to put inside
the box and your computer specs in some ways.

Given that the drives are identical then an external USB set up
will be slower?

Why do many users install external drives when there is a spare
internal slot. At least that is my impression, perhaps mistaken,
that this commonly is the case.

USB 2.0 and 1394 are quick interfaces, but keep in mind that they are not as
fast as a SATA or ATA interface. In general - yes - an internal hard disk
drive will have the capability of being faster than an external hard disk
drive (given identical hard disk drives are utilized in the tests.)

Let's compare the maximum *possible* performance of each interface.

-- USB 1.1 - 12 Mbits/sec
-- USB 2.0 - 480 Mbits/sec
-- USB 3.0 - 4.8Gbits/sec

-- 1394a - 400 Mbits/sec
-- 1394b - 800 Mbits/sec

-- UltraATA 100 - 100 Mbytes/sec

-- SATA - 1.5 Gbits/sec
-- SATA II - 3.0 Gbits/sec

So - why do people get external hard disk drives? (USB 3.0 is not available
that I know of yet - but, yeah - that one might be faster than the rest when
it comes out. hah)

A few possibilities run through my skull.
- Easy. Most people may not even think about opening their computer case.
- Portable media. Maybe they want to carry it someplace.
- External to the computer backups. It's easier to grab that external hard
drive you back up to regularly and get out than get the entire computer.

 

[Gerry]

Thanks Shenan

That's given me something to think about.

Was this a typo?
UltraATA 100 - 100 Mbytes/sec

What does UDMA Supported Mode and UDMA Active Mode mean? I can guess but
would like to be sure I am getting it right.


--
Regards.

Gerry
~~~~
FCA
Stourport, England
Enquire, plan and execute
~~~~~~~~~~~~~~~~~~~

 

[R. McCarty]

The "Technology Interface" is the controlling factor. Only eSATA
provides throughput or sustained transfer rates similar to internal
drives. I use two different eSATA drives on my primary system
and each achieve 80+ Megabytes-Per-Second. USB2.0 drives
are generally limited to around 25-Megabytes-per-Second. It's
convenient but USB2.0 is not as efficient as eSATA. External
cases that use a "Translator" chipset ( PATA to USB ) adds a
little more overhead and limits the drive's maximum throughput.

 

[Ken Blake, MVP]

Why do many users install external drives when there is a spare internal
slot. At least that is my impression, perhaps mistaken, that this
commonly is the case.

If the drive is used for backup, as many external drives are, that's
the *only* way to do it, as far as I'm concerned. Backup needs to be
to removable media, not kept in the computer. Backup to an internal
drive is unacceptable because it leaves your data and its backup
subject to simultaneous loss by many of the most common dangers: user
error, nearby lightning strike, virus attack, even theft of the
computer. As has often been said, it's not a matter of whether you
will have such a problem, but when.

 

[Lil' Dave]

UDMA100 or ATA100 can theorectically go 100 MB/sec. ATA133, 133 MB/sec.
Most you will probably see in reality is 80 MB/sec for either. This is on
its native interface, not USB.

If the potential USB 3.0 is like the 1394B, both faster than the ATA hard
drive can pass data, it will glitch out waiting for data.

--
Dave
..

Thanks Shenan

That's given me something to think about.

Was this a typo?
UltraATA 100 - 100 Mbytes/sec

What does UDMA Supported Mode and UDMA Active Mode mean? I can guess but
would like to be sure I am getting it right.


--
Regards.

Gerry
~~~~
FCA
Stourport, England
Enquire, plan and execute
~~~~~~~~~~~~~~~~~~~