This is an informal test of the speed of various external drives. The test was conducted in the following way:
- Copy a 29 GB file from an external drive to a 2022 Macbook Air — this is to test the drive’s read speed
- Then copy same the file back to the drive — this is to test the drive’s write speed
Samsung Duo Plus Flash Drive — USB 3.1

The Samsung Duo Flash Drive is a flash drive that supports both USB-A and USB-C connections.
For a 29 GB file, the actual time to copy was: 1:38 (read) and 14:10 (write)
The tested read speed was 296 MB/s.
Sandisk Ultra FIT Flash Drive — USB 3.1

The Sandisk Ultra FIT Flash Drive is one of the largest capacity Flash Drive currently available — with a capacity of 512 GB.
For a 29 GB file, the actual time to copy was: 3:23 (read) and 15:50 (write)
The tested read speed was 143 MB/s.
Shadow Mini Portable SSD — USB 3.1

The Shadow Mini Portable SSD is a speedy, high-capacity drive.
For a 29 GB file, the actual time to copy was: 1:40 (read) and 2:01 (write).
The tested read speed was 290 MB/s.
Seagate Slim HDD — USB 3.0

This is a Seagate Slim HDD.
For a 29 GB file, the actual time to copy was: 5:12 (read) and 6:30 (write).
Hard Drives (HDD) tend to have slower read speeds than Flash Drives and Solid State Drives (SDD). However, they will almost always have faster writer speeds than Flash Drives.
The tested read speed was 92 MB/s.
Western Digital My Passport HDD — USB 3.0

This is a Western Digital My Passport HDD. As with the Seagate Hard Drive, this drive has a slower read speed than an SDD External Drive.
For a 29 GB file, the actual time to copy was: 4:00 (read) and 4:18 (write)
The tested read speed was 120 MB/s.