This experiment uses 32GB SanDisk Dual Drive that has 2 connectors: normal full-sized USB 3.0 and the new USB-C (also known as USB Type-C) connectors. My aim is to compare the speed of this particular flash storage when being accessed from both connectors. For this test, I use an iMac with built-in USB 3.0 ports and a Macbook with built-in USB-C port. I prepared three sets of data to be written to, and read from the micro SD cards:
- Data A is 1 large file. The size is 4.25 GB.
- Data B is a set of 12 medium files. The total size is 5.81 GB.
- Data C is a set of 45,976 small files. The total size is 5.47 GB.
Testing process is simple. First I formatted the SanDisk Dual Drive using ExFAT so at the beginning of the test, they are empty. The formatting uses standard ExFAT from Windows with all default settings. To measure WRITE speed, I copied each set of data into each memory card and timed the process. To measure READ speed, I copied back those sets of data back into my computer and timed the process. To perform the file transfers, I use a tool named ChronoSync 4.6.2. This is a backup app for Mac, but I have good experience using it as file copier because it performs generally faster than using the standard Finder.
| Operation | Data | Full-sized USB 3.0 |
USB Type-C |
| WRITE | A | 1 min 57 secs avg speed 37.20 MB/s |
1 mins 58 secs avg speed 36.88 MB/s |
| WRITE | B | 2 mins 47 secs avg speed 35.62 MB/s |
2 mins 54 secs avg speed 34.19 MB/s |
| WRITE | C | 1 hour 24 mins 52 secs avg speed 1.10 MB/s |
58 mins 4 secs avg speed 1.61 MB/s |
| READ | A | 59 secs avg speed 73.76 MB/s |
1 min 10 secs avg speed 62.17 MB/s |
| READ | B | 1 min 21 secs avg speed 73.44 MB/s |
1 min 38 secs avg speed 60.70 MB/s |
| READ | C | 12 mins 19 secs avg speed 7.58 MB/s |
12 mins 7 secs avg speed 7.70 MB/s |
The results of this experiment is surprisingly consistent. For this particular product, USB-C connector works faster with a lot of small files while full-sized USB 3.0 works faster with large and medium files. Of course, I am going to state the obvious here: this does not indicate the speed of full-sized USB 3.0 vs. USB-C itself. This simply shows that SanDisk’s specific implementation of both connectors in this particular product showed such results.
Steve Knapp is totally right. This test does not say much for connections.
The circuitry within that device could be bad/worse on the C side.
Does the C side use a faster BUS chip/circuit?
Hi. Interesting tests. However, I suspect that what you have tested is not the difference between USB 3.0 and USB C. You have tested the difference between the iMac with an unknown hard disk and an unknown disk bus speeds with a USB 3.x port and a Type A socket vs. a Macbook with a USB 3.x port and a Type C socket and who knows what disk, bus speeds, cpu speeds, etc.
USB C is not a protocol or a bus or a speed rating, etc. It is just a connector. There is USB A and USB B and USB mini and USB micro,and the new USB C connectors.
Independent of connectors, there is USB 1, USB 1.1, USB 2.O, USB 3.O, USB 3.1, etc.
Most likely, if you had a computer with USB A and USB C sockets, it wouldn’t make virtually no difference which end of this USB 3.x stick you used.