Memory sticks have come a long way in recent years. Not only do they hold a lot more files (the SanDisk 64G Dual Drive USB-C Flash Drive has 64 Gigabytes!), but the USB interface itself is faster. I was excited to try out this flash drive with my USB Type-C enabled LeEco Le 1s phone.

Read and Write Performance

I made some measurements of the read and write speeds, because I was curious to see whether the SanDisk 64G Dual Drive USB-C Flash Drive device used USB 2.0 (480 Mbs/) or USB 3.1 Gen1 (5 Gbs/) speeds, even when attached using the USB Type-C connector. For the test, I created a new folder on the SanDisk drive using a Apple MacBook Pro (Mid 2015), and copied enough large files to fill the folder to about 800 MBytes.

I wanted to check the write speeds and the read speeds, through this admittedly crude technique.

I used a short adapter cable to allow me to connect the Sandisk's Type-C plug to the LeEco's Type-A port.

As a benchmark, I tried sharing files between my Apple MacBook Pro (Mid 2015) and the SanDisk 64G Dual Drive USB-C Flash (plugged into a Super Speed USB 3.1 Gen 1 Type-A port):

• Writing from SanDisk to the Mac ..... 10 seconds
• Writing from Mac to the SanDisk ..... 30 seconds

When sharing files between the LeEco Le 1s and the SanDisk 64G Dual Drive USB-C Flash (plugged through a USB Type-A adapter):

• Writing from SanDisk to the LeTV ... 35 seconds
• Writing from LeTV to the SanDisk ... 23 seconds

When sharing files between the LeEco Le 1s and the SanDisk 64G Dual Drive USB-C Flash device (plugged through a USB Type-C port):

• Writing from SanDisk to the LeTV ... 27 seconds (about a 23% reduction in time)
• Writing from LeTV to the SanDisk ... 14 seconds (about a 40% reduction in time)

Well, that was satisfying to see the improved performance for USB Type-C over Type-A.

Next I downloaded the USB Device info App onto the LeTV 1s to check the speed of the USB link being used. (Click here to see how to check the USB speed of your device connected to an Android phone)

In all cases the phone was in USB 2.0 High Speed mode (no Super Speed USB here). So what's going on? How to explain the performance variations?

USB Adapter

On close examination I found that the Type-C to Type-A adapter actually carries through all nine conductors needed for USB 3.1. So, the adapter itself is not limiting the selected USB mode.

SanDisk Flash Drive

Examining the Type-A plug on the SanDisk 64G Dual Drive USB-C Flash, I see the same nine conductors as are in the adapter. Yes, the Type-A plug is USB 3.1 capable. I then looked closely at the Type-C plug and again see all nine conductors! So, like the adapter, this is a USB 3.1 capable Flash device at least on both plug connectors.

The photo on the left is the Sandisk's USB Type-A plug, without the blue that many companies use to distinguish USB 3.1 from USB 2.0 device.  For example, in the photo on the right, the Kingston DataTraveler microDuo 3C has a blue USB Type-A plug to distinguish it from a USB 2.0 Type A plug.  I guess SanDisk decided to not use the blue to make it consistent with Apple Mac's also not using blue on their USB 3.1 Type-A ports.

 

LeTV 1S Phone

Now we come to the final piece in the puzzle. The USB Device info App showed that USB 2.0 mode was selected, so does the Phone support USB 3.1 on USB Type-C?

I connected the SanDisk 64G Dual Drive USB-C Flash (labeled as the Realtek chip that is inside the drive) in the photo on the left, below), and the Kingston DataTraveler microDuo 3C (the photo on the right, below) to the LeEco Le 1s Type-C connector. The App showed that both connected using High Speed USB 2.0.

  

To check the USB speed capabilities of the SanDisk 64G Dual Drive USB-C Flash, I connected it to a Type-C connector of a laptop known to support USB 3.1. Using a program called USB Device Viewer, I confirmed that the SanDisk drive does support USB 3.1 Super Speed mode, as shown in the photo below:

Questions Remain:

The LeEco Le 1s does not support USB 3.1 on its Type-C connector, and only supports USB 2.0 High Speed mode (this is confirmed on LeEco's India shopping site).  So if the connection for both the USB Type-A and Type-C parts of the SanDisk 64G Dual Drive USB-C Flash are high speed, what would explain the performance difference between USB Type-A and Type-C?  We'll find out and share more with you later.

Mounting and Un-mounting the SanDisk Device

Android asks that the user un-mount the USB device before unplugging it. Unfortunately, the place to do this is in Settings, under Storage. You have to look carefully, and the warning window is a bit intimidating! You may see that, after accepting the Unmount with OK, the External USB storage disappears from the Storage Settings screen.

  

 

Mounting and unmounting a drive is a bit awkward, but without properly unmounting the device you will get a warning message.

In conclusion, the SanDisk 64G Dual Drive USB-C Flash Drive works well with the LeEco Le 1s.  Definitely make use of the USB Type-C connector which is more convenient and is for some reason faster than the USB Type-A connector.