The Plugable USB 3.0 Multi-Card Reader and Linux

August 6, 2014
cd03Do you need a way to read external memory cards, such as SD and Memory Stick Duo, from Linux? How about a faster card reading method than using an external device, such as a camera?

If so, then here is an inexpensive, fast performer that is 100% plug-and-play compatible with Linux: The Plugable USB 3.0 Multi-Card Reader!

Yes, the name sounds plain, but I have found this to live up to its packaging boasts with impressive reliability.

Packaging

The packaging appears generic, but this is the real deal. It truly performs as advertised with USB 3. I have found that speeds are limited by the speed and quality of the media cards, not the card reader itself.

a

Front of package.

Back of the packaging. All compatible cards are listed as well as operating system compatibility.

Back of the packaging. All compatible cards are listed as well as operating system compatibility.

Operating Systems

The card reader supports Mac OS, Windows XP/Vista/7/8, and…Linux! While other products might be Linux-compatible yet not mention the fact, this is one of the products I have seen recently that goes out of its way to list Linux compatibility on the package.

Linux Usage

Driver installation is unnecessary with Linux. I have used this with Ubuntu 14.04, Linux Mint 17, and Xubuntu 14.04, and all of them immediately detected the card reader. As soon as a card is inserted, a file manager opens (depending upon the system configuration) to display the card. This device could not be easier to use. Just use it like any other drive. When finished, safely eject the media.

Even though this is a USB 3 device, it is backward compatible with USB 2 ports. However, the transfer speeds might be limited with USB 2 depending upon the maximum speed of the card. Slower cards will perform identically with both USB 2 and USB 3.

Supported Cards

There are three slots that accept memory cards, and they only accept the SD/Micro SD/Memory Stick styles. Other types are not supported.
Slots:

Micro SD            Accepts Micro SD cards
SD/SDHC/SDXC/MMC    Accepts the SD-type cards
MS/MSXC             Accepts Sony Memory Stick and Memory Stick Duo cards
a

Three slots accept various cards. Shown here is a Samsung EVO micro SD card in the micro SD slot. Use one slot at a time.

Only one slot/card can be used at a time. You cannot insert three different cards and expect to access all of them simultaneously in three separate file managers. You would need another card reader for that. Work with one card at a time.

It is possible to place cards of one type into an adapter. For example, you can put two micro SD cards in a Memory Stick Duo adapter, which the card reader will see as a single 128 GB Memory Stick Duo provided it has been formatted as a 128 GB card.

a

126 GB Memory Stick Pro Duo made from two 64 GB Micro SD cards fit into a Duo adapter. The micro SD cards used here only formatted to 126 GB, not 128 GB.

Why Would I Want to Use This?

“My camera already connects to my computer via USB, so I can already read the memory card. Why would I need an external adapter?”

For myself, there are three reasons: Speed, electrical power, and extra ports.

Speed. Many older cameras might offer a USB connection, but they are limited to USB 2 and the USB 2 implementations of those devices are often much, much slower than the maximum offered by USB 2. Lengthy file transfers take a long time.

Power. During these lengthy transfers, the camera’s battery must last long enough to complete the transfer. I have encountered cases where the external device had no external power supply, so I had to wait for a full battery charge in order to complete a file transfer. Or, I had to transfer in sessions — recharging between each session.

Extra Ports. Some netbooks and Ultrabooks might have an SD slot that accepts SD cards, but nothing else. Connecting this to a USB port makes it possible to access different types of cards.

 

Everyday Usage

In everyday usage, I found little difference between USB 2 and USB 3 with the card reader because the memory cards I used were older and slower than today’s modern offerings. A Class 10 SD card reads and writes at the same speed using both USB 2 and USB 3 because it does not exceed the limits of USB 2. I would need a 40-50+ MB/s card in order to see the advantages of USB 3.

However, directly accessing the cards with the card reader is certainly faster than using the device, such as a camera. The camera I tested has a USB 2 interface that is slower than a computer motherboard’s USB 2 port. By reading and writing the card directly, the “middleman” is eliminated, and card transfers are much faster.

 

Benchmarks

Here are a few benchmarks to get an idea of the read/write speeds possible using this card reader with everyday memory cards. All tests were conducted using the Disks program in Linux Mint 17 with kernel 3.16.0.

The card reader was connected to USB 3 and USB 2 ports for comparison to see if USB 3 made any difference with the tested cards, and all tests were measured using the Disks Benchmark test with 100 samples of 10 MB each. All cards were formatted to FAT32.

Keep in mind that a slow memory card will not read faster in USB 3. If a card is limited to 10 MB/s with USB 2, then it will still be limited to 10 MB/s with USB 3.

 

Standard 16 GB SD (Class 10)

USB 3
 ---------------------------
 Read: 20.0 MB/s
 Write: 6.7 MB/s
USB 2
 ---------------------------
 Read: 20.0 MB/s
 Write: 6.7 MB/s
a

16 GB SD Card in USB 3.

b

16 GB USB Card in USB 2.

Same read/write speeds for both USB 2 and USB 3. This is a limitation of the card’s speed. But watch what happens when we insert this card into a camera and read it using the camera’s USB 2 interface.

 

Camera 16 GB SD Card (Connected to USB 3 Port)
 ----------------------------------------------
 Read:  7.0 MB/s
 Write: 4.1 MB/s
c

16 GB SD Card read using camera connected to USB 3 port. Camera has a USB 3 interface.

Same card, but significantly slower than reading the card directly using the card reader. Plus, the camera is powered by a battery. Given lengthy file transfers, the battery can deplete before finished transferring all files.

SanDisk Ultra 64 GB Micro SD

USB 3
 ---------------------------
 Read: 30.2 MB/s
 Write: 7.0 MB/s
USB 2
 ---------------------------
 Read:  32.3 MB/s
 Write:  6.9 MB/s
USB 3

USB 3 – 64 GB Micro SD

USB 2

USB 2 – 64 GB Micro SD

 

USB 3 and USB 2 perform about the same speed with the same card. Since USB 2 will operate at about 40-48 MB/s at the most, we will not see an advantage until we use cards exceeding those speeds. But this is not always the case. Look at the speeds when this card is benchmarked using a PSP (PlayStation Portable).

PSP (One 64 GB Micro SD in MS Pro Duo Adapter. Connected to USB 3 Port)
 -----------------------------------------------------------------------
 Read:  8.0 MB/s
 Write: 4.9 MB/s
PSP

PSP – 64 GB Micro SD in Memory Stick Pro Duo Adapter

Even though the card is capable of the faster read/write speeds shown above, the PSP’s USB 2 interface is throttling the data transfer.

 

Sony 4 GB Memory Stick Pro Duo MARK 2

Now, let’s have a look at a genuine Memory Stick Duo.

USB 3
 ---------------------------
 Read: 10.2 MB/s
 Write: 7.3 MB/s
USB 2
 ---------------------------
 Read: 10.2 MB/s
 Write: 7.3 MB/s
USB 3

USB 3 – 4 GB Memory Stick Pro Duo MARK 2

USB 2

USB 2 – 4 GB Memory Stick Pro Duo MARK 2

126 GB MS Pro Duo (Two 64 GB Micro SD in one MS Duo Adapter)

The Memory Stick Pro Duo is mostly used with Sony cameras, but it tends to be an expensive memory card format. However, adapters exist that allow you to use the cheaper, smaller micro SD cards in Memory Stick Pro Duo devices. Here, two micro SD cards are fitted into a dual adapter to produce a Memory Stick Pro Duo card of 126 GB. The device the adapter is used in never knows the difference. Speeds tend to be faster than the official Sony cards, but slower than if reading the micro SD cards by themselves.

USB 3
 ---------------------------------
 Read:  17.1 MB/s
 Write: 11.8 MB/s
USB 2
 ---------------------------------
 Read:  17.1 MB/s
 Write: 11.5 MB/s
USB 3

USB 3 – 126 GB using two 64 GB Micro SD

USB 2

USB 2 – 126 GB using two 64 GB Micro SD

PSP - 126 GB Connected to USB 3 Port
 ------------------------------------
 Read:  9.2 MB/s
 Write: 7.3 MB/s
PSP

PSP – 126 GB using two 64 GB Micro SD cards

Here, the 126 GB memory card is inserted in the PSP, which is connected to the computer for benchmarking.  Even though it is the same 126 GB card tested previously, the read/write speeds are significantly slower when accessed using the PSP.

This demonstrates the advantage to using an external card reader over using the devices themselves to read the cards. Speed. From these tests involving a camera and a PSP, the card reader offers faster performance.

 

Conclusion

I am pleased. With this card reader, I have been able to access all of my SD and Memory Stick cards at faster rates than what is possible using cameras and other devices. The card itself becomes the limiting factor, and USB 3 allows for growth in the future should I obtain faster memory cards that operate in the 50+ MB/s range.

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