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Is it possible to use Apricorn's SATA Wire 3.0 with a normal 3.5" desktop drive?

According to the Apricorn FAQ this is not possible:

Will the SATA Wire work with desktop size drives?

No. Desktop drives require both 5 volt and 12 volt signals. The SATA Wire gets power from the USB port, which can only provide the 5 volt signal.

But will it work if I attach an extra power cable from the computer to the drive, or will that fry the disk?

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It might work. But if you are already plugging extra power from the desktop why not plug in power and a SATA cable? –  Hennes Sep 7 '12 at 14:45
    
Because that would be to easy ;-) –  mhu Sep 7 '12 at 20:16
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1 Answer 1

up vote 2 down vote accepted

Let me give a proper long answer on this (rather than the comment from earlier).

1) Provided power

USB provides minimal power on the USB bus. This is supposed to be just enough to power some electric circuitry. If a device on the USB bus needs more power it needs to ask for it. Depending on how much more power can be delivered this might be granted or not.

For USB 1 and USB 2 this is maximum 500mA at 5 volt (max 5 Watt). For USB 3 this can be up to 900mA at 5 volt.

2) Power used by drives

A typical 3½ desktop drive uses up to 15 Watt at start up, and about 5 to 10 Watt when mostly idle. Obviously this depends per drive. a 15K RPM SAS drive is likely to use a lot more power then a 5400RPM drive. Both however are fed with +5 volt and +12 volt.

USB can not provide enough power for these. Even if you convert some of the supplied +5 volt line to +12 volts. 5 or 9 Watt just is not enough

3) But it works for laptop drives!

Laptop drives usually use only +5 volt and draw less power. Most USB powered drives in an external casing are 5400 RPM drives drawing just shy of the max power supplied by the USB 1/USB2 bus. Some drives use more and use an ugly hack with two USB cables to try to draw more power. Sometimes this works. Sometimes it does not.


If you still want to use a regular desktop drive via USB then you will need to supply it with power from an other source than the USB bus. This can be done both via en external power supply or via another source. I cable from the desktops PSU to which you are connecting the drive will work, but has the following disadvantages over just connecting the drive via SATA:

  • More complex (No need to use that Apricorn wire. Just use a plain simple cheap SATA cable)
  • Slower. [Drive SATA->motherboard SATA] will be faster than [Drive SATA->Wire SATA-> USB-> Motherboard]. It will also have much less protocol overhead.
  • No extra drivers needed.

The only advantage in the product you mention seems to be if you want to connect a 2½ inch quickly and easily. It does not provide that for desktop drives.

If you want to connect both laptop and desktop drives quickly and easily, google for an external SATA dock. Preferably with eSATA. (Here is an example of such a dock. Do not buy that one, it is twice as expensive as needed).

Here is a picture of such a dock (The dust on it indicates that I need to clean my workroom more often. ;-) )

HDD dock

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