What are the Best Dual Flash Drives?
We tested four dual flash drives from Kingston, Sandisk, Silicon Power and Sony. These USB 3.1 Gen. 1 drives serve as a bridge between USB-C and legacy USB-A devices, offering you the best of the both worlds.
November 2017 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
 KingstonDT microDuo 3C |  SandiskUltra Dual Drive |  Silicon PowerMobile C31 |  SonyUSM-CA1 |
|
|---|---|---|---|---|
| Storage: | 16 - 128GB | 16 - 256GB | 16 - 64GB | 16 - 64GB |
| Android File Manager? | No | Sandisk Memory Zone | SP File Manager | No |
| 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 |
| Dimensions: | 29.9 x 16.6mm x 8.4mm | 38.1 x 20.1 x 9.4mm | 33.2 x 12.3 x 8.5mm | 26.35 x 12.2 x 5.3mm |
| Weight: | 4.5g | 9.1g | 3.3g | 5g |
| Build Material: | Plastic & metal | Plastic & metal | Plastic & metal | Metal |
| USB Connector Protection? | Rotating cap for USB-C | Retractable connectors | Swivel cap | No |
| Color(s): | Silver | Black & silver | Silver & grey | Silver |
| Release Date: | July 2015 | May 2016 | July 2017 | Jan 2016 |
| Warranty: | 5 years | 5 years | Lifetime | 2 years |
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Benchmark Analysis
We carried out our benchmarks on two different platforms – Apple MacBook Pro and Samsung Galaxy S8 – for the four dual-headed drives. The Galaxy S8 – 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 the 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.
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
| Kingston DT microDuo 3C | Sandisk Ultra Dual Drive | Silicon Power Mobile C31 | Sony USM-CA1 |
|
|---|---|---|---|---|
| 5GB Movie Read Speed: (USB Drive to PC) | 42.11MB/s | 142.21MB/s | 211.32MB/s | 123.18MB/s |
| 5GB Movie Write Speed: (PC to USB Drive) | 14.34MB/s | 27.48MB/s | 29.24MB/s | 16.45MB/s |
| 5GB Photos Read Speed: (USB Drive to PC) | 38.70MB/s | 100.98MB/s | 165.75MB/s | 89.72MB/s |
| 5GB Photos Write Speed: (PC to USB Drive) | 13.41MB/s | 17.56MB/s | 26.87MB/s | 12.26MB/s |
| 5GB Movie Read Speed: (USB Drive to Samsung S8) | 75.32MB/s | 65.81MB/s | 88.84MB/s | 67.56MB/s |
| 5GB Movie Write Speed: (Samsung S8 to USB Drive) | 21.3MB/s | 21.56MB/s | 21.98MB/s | 20.52MB/s |
| 5GB Photos Read Speed: (USB Drive to Samsung S8) | 68.83MB/s | 57.52MB/s | 76.33MB/s | 53.8MB/s |
| 5GB Photos Write Speed: (Samsung S8 to USB Drive) | 14.27MB/s | 21.31MB/s | 18.91MB/s | 20.35MB/s |
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 their USB connectors, Kingston and Silicon Power opt for the swivel cap whereas Sandisk chooses retractable design. Sony, on the other hand, provides a silicone case for its bare drive.
Practically speaking, the Sandisk and Silicon Power are better for daily use as we didn’t have to wait for the drives 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.
Some of these drives provide their own Android backup and file management app. We didn’t have any lucky getting our Sandisk Ultra Dual recognized by the company’s Memory Zone app and Silicon Power’s SP File Explorer is more or less the same as the the file manager found on our Samsung S8. So, unlike iOS flash drives, app support doesn’t really make or break a dual flash drive.
The Best Dual USB Drives
Out of the four 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.