What are the Best Dual Flash Drives?

 July 2018         Ian Chiu

 Do I need a Dual Flash Drive?

Dual flash drives – having USB Type-A and USB-C connector on opposite ends – are becoming more relevant as more computers and smartphones ship with the reversible USB port exclusively.  They make sure you have readily access to your data on your future-proof USB-C devices as well as giving you backward compatibility on PCs and Macs with good old USB Type-A.  For this reason, it will never hurt to have at least one of these dual-headed flash drives in case you need a quick and easy file transfer solution.

Feature Comparison

	Kingston DT microDuo 3C	PNY Duo Link OTG Drive	Sandisk Ultra Dual Drive	Silicon Power Mobile C31	Sony USM-CA1
Storage:	16 - 128GB	32 - 128GB	16 - 256GB	16 - 64GB	16 - 64GB
Interface(s):	USB 3.1 Gen 1 Type-A USB 3.1 Gen 1 Type-C	USB 3.1 Gen 1 Type-A USB 3.1 Gen 1 Type-C	USB 3.1 Gen 1 Type-A USB 3.1 Gen 1 Type-C	USB 3.1 Gen 1 Type-A USB 3.1 Gen 1 Type-C	USB 3.1 Gen 1 Type-A USB 3.1 Gen 1 Type-C
Dimensions:	30 x 16.6 x 8.4mm	50.8 x 25.4 x 8.9mm	38 x 20.1 x 9.4mm	33.2 x 12.3 x 8.5mm	26.4 x 12.2 x 5.3mm
Weight:	4.5g	8.2g	9.1g	3.3g	5g
Build Material:	Plastic & metal	Plastic	Plastic & metal	Plastic & metal	Metal
USB Plug Protection?	Rotating cap for USB-C	Retractable connectors	Retractable connectors	Swivel cap	No
Color(s):	Silver	Black	Black & silver	Silver & grey	Silver
Android File Manager?	No	No	Sandisk Memory Zone	SP File Manager	No
Release Date:	July 2015	April 2018	May 2016	July 2017	Jan 2016
Warranty:	5 years	1 year	5 years	Lifetime	2 years

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Benchmark Analysis

We carried out our drive benchmarks on two different platforms – Apple MacBook Pro (2014) and Samsung Galaxy S8 Plus.  The Galaxy – the first (or second if you count Note 7) flagship phone from Samsung to come with USB-C – was chosen because of its popularity whereas the MacBook Pro was selected for legacy USB-A connectivity.

Kingston claims read speed of 100MB/s over USB Type-A for its MicroDuo 3C.  The corresponding numbers are 150MB/s and 130MB/s for Sandisk Ultra Dual and Sony USM-CA1 respectively.  Silicon Power, however, doesn’t advertise its drive speed for its Mobile C31 so we didn’t know what to expect in terms of performance.  Lastly, PNY’s Duo Link OTG can reportedly reach up to 130MB/s in ideal conditions.

Our testing with the USB Type-A interface involved transferring a 5GB MP4 file back and forth between our Mac and the drives.  We repeated the process with a folder containing 1000 JPEGs.  As you can see in the graph above, Silicon Power Mobile C31 was clearly ahead with rest of the drives but the advantages greatly diminished during small file transfers.  There’s also something peculiar to the Kingston MicroDuo 3C as the drive consistently fell short of its advertised speed.

Next we looked into the kind of performance you can expect if you plan on using these dual-headed drives for regular photo backups and large video imports on a Samsung Galaxy S8.  The smartphone is equipped with USB-C capable of delivering 5Gbps, just like almost every other Android handset released in 2017.  For this set of benchmarks, we repeated the same procedures on USB-C as we did with the legacy USB-A on our Mac.

From the graph above, the Mobile C31 from Silicon Power continued to lead by a fair margin in large file transfers.  The drive, however, was neck and neck with the others when copying photos.  The MicroDuo 3C from Kingston did manage to hold its own in spite of its disappointing performance on USB Type-A.

Benchmark Data

Drive Design & Features

Manufacturers took different approach in the design with their dual flash drives but there’s nothing we haven’t seen before.  To protect the USB connectors, Kingston and Silicon Power opt for the swivel cap whereas Sandisk and PNY choose retractable connector design.  Sony simply provides a silicone case for its drive.

Design-wise, the Sandisk and Silicon Power are better for daily use as we didn’t have to wait for either drive to cool down before pulling them out from a USB port.  In the case of Sony and Kingston, we had to wait half a minute or so because these bare drives might get too hot to handle after several minutes of intense I/O operations.  The PNY, however, doesn’t exactly have the best sliding mechanism as the slider sometimes makes it difficult to reveal and retract the USB connectors.  The drive also feels somewhat flimsy compared to other models tested here.

On the software side, some of these drives provide their own Android backup and file management app.  That is the case with Sandisk and Silicon Power.  However, we didn’t have any lucky getting our Sandisk Ultra Dual recognized by the company’s Memory Zone app.  Silicon Power’s own file explorer is also more or less the same as the stock file manager found on our Samsung S8 Plus.  Since there’s an abundance of third-party file browser apps on Google Play Store, you’ve plenty of options when it comes to managing files on your USB drives on Android.

 The Best Dual USB Drives

Out of the five drives we tested, Silicon Power Mobile C31 has proved to be a better performer in terms of design and performance.  Its swivel cap also serves as a great handle for pulling the drive from a port, especially if the drive heats up considerably after long use.  The second best is the Sandisk Dual Ultra Drive should you prefer its slider and all-around protection.

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