SSD Power Ratings on Label--Relevant for Bus-Powered External Enclosures?

[sarangiman]

I want to use SSDs in USB 3.0 bus-powered enclosures.

My question is about the power rating of drives & the 900mA standard of power available over the USB 3.0 bus.

I've already tested a number of SSD/enclosure combos. In all cases, there seem to be some reliability issues.

Enclosures I've tested:

1. Siig USB 3.0 SATA 6Gb/s Enclosure
2. Buffalo MiniStation Thunderbolt
3. Seagate Thunderbolt Adapter
4. Seagate GoFlex Slim USB 3.0

Drives I've tested:

1. Intel 520 480GB (rated: 5V 1A)
2. Crucial M4 512GB (rated: 5V 2A)
3. Samsung 830 128GB (rated: 5V 1.6A)

These aren't huge reliability issues, just every now and then a disk benchmark fails b/c it can't read from the disk, or a huge directory transfer fails b/c a file can't be read. Doesn't happen often, and when it does, you can just run the benchmark/file copy again, and usually it's fine.

I'm wondering if this is due to power issues.

I'm always connecting the drive with one USB 3.0 cable (not 2 w/ a Y splitter). Each USB 3.0 port is rated at 900mA, right?

Well, the drive's voltage/amps ratings are all indicated in bold above (read off the label on the drive).

Do these numbers have any meaning in the context of the 900mA current available over the USB 3.0 port?

Though I haven't tested the failure rate objectively/scientifically, I feel so far that the Intel 520 drive has had the least number of failures (only failed once I think), whereas the Crucial M4 & the Samsung 830 have already failed like 3 times in the USB 3.0 enclosures.

Certainly, if you look at Anandtech's power consumption charts:
http://www.anandtech.com/show/5817/the-intel-ssd-330-review-60gb-120gb-180gb/8

It would seem that in terms of power consumption during read/writes, in general:

Intel 520 < Crucial M4 < Samsung 830

Which almost jives with the amp ratings on each drive's label (1A, 2A, & 1.6A for Intel 520, Crucial M4, & Samsung 830, respectively).

Older 2.5" platter-based drives had ~0.5A on their labels, or less, for 5400rpm drives, & 0.7-1A for 7200rpm drives.

So those numbers for older 'spinny' drives seem to be considerably lower than those for a lot of these SSDs.

Is that why not many manufacturers are making external bus-powered SSDs? Or why the Siig enclosure came with a Y-splitter USB cable.

In this case, for single-cable, bus-powered USB 3.0 enclosures, would you recommend the lowest power consumption drives available (looks like Intel to me)?

Many thanks in advance!

 

[Leo8186]

I'm very suprised that this question got no answer as the problem seems to be effective.

USB 3.0 enclosures, are designed for 900 mA.
The circuitry of some can tolerate up to 1100 mA (LC-Power LC-25BUB3 for instance).
But we are far below the theorical 2A consumption of Crucial M4 drives.

I tried a Crucial M4 inside an Icy Box IB-254U3 which is designed for high speed SATA III drives and supports USAP. Strangely the circuitry of the enclosure was not damaged, but the Crucial M4 512 GB was not recognized by some computers and died after less than 1 day. Maybe I was just unlucky with this SSD but given the price of such SSD it scares me to try with other ones.

Some enclosures have a wire with two USB sockets at one end. For instance the LC-Power LC-25BUB3. Could this be to allow a higher current ?

 

[Eug]

I would recommend getting a USB 3 enclosure that can be both bus powered and which can accept an AC adapter.

While certain drives may support bus-only power, many don't, and furthermore, the results are hit and miss (as you've discovered) regardless of what the numbers seem to say.

The Y-splitter cables are also not reliable ways to make this work, since it depends on the reliability of the source ports.

The only way to be 100% sure it will work is to have an AC adapter option.

Oh and BTW, a single failure is a big deal IMO.