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TR RoboBench — Real-world transfers
The first time we benched a portable SSD, it was the first USB storage device to be tested on our current storage rigs. Thus, we hatched a plan to test it against a USB-docked SATA drive to provide a point of reference. This time around, we've dispensed with the drive dock, since we have our existing data from Samsung's Portable SSD T3 and Portable SSD T5 to work with.

RoboBench comprises real-world transfers with a range of file types. Developed by our in-house coder, Bruno "morphine" Ferreira, this benchmark relies on the multi-threaded robocopy command build into Windows. We copy files to and from a wicked-fast RAM disk to measure read and write performance. We also cut the RAM disk out of the loop for a copy test that transfers the files to a different location on the SSD.

Robocopy uses eight threads by default, and we've also run it with a single thread. Our results are split between two file sets, whose vital statistics are detailed below. The compressibility percentage is based on the size of the file set after it's been crunched by 7-Zip.

  Number of files Average file size Total size Compressibility
Media 459 21.4MB 9.58GB 0.8%
Work 84,652 48.0KB 3.87GB 59%

The media set is made up of large movie files, high-bitrate MP3s, and 18-megapixel RAW and JPG images. There are only a few hundred files in total, and the data set isn't amenable to compression. The work set comprises loads of TR files, including documents, spreadsheets, and web-optimized images. It also includes a stack of programming-related files associated with our old Mozilla compiling test and the Visual Studio test on the next page. The average file size is measured in kilobytes rather than megabytes, and the files are mostly compressible.

RoboBench's write and copy tests run after the drives have been put into a simulated used state with 30 minutes of 4KB random writes. The pre-conditioning process is scripted, as is the rest of the test, ensuring that drives have the same amount of time to recover.

Let's take a look at the media set first. The buttons switch between read, write, and copy results.

With a single thread, speeds are dead even between the SD700 and the much larger T3 2TB. The Samsung drive's size advantage becomes much more apparent with eight threads, where the T3's write performance leaves the Adata drive in the dust. Good thing the SD700 is dust-proof. Despite trailing the T3, the SD700's transfer speeds are plenty fast enough for external storage.

Next up, the work set.

The gap completely disappears in the work set. In both single- and eight-threaded testing, the two drives are neck-and-neck. The T3's gargantuan capacity doesn't lend it much of a speed advantage when it comes to the more random-I/O-heavy work set.

If you only consider USB 3.0 external SSDs, Samsung's 2TB Portable SSD T3 might claim a victory in eight-threaded sequential transfers, but by and large, the SD700 is able to keep up. Adata's external is a potent portable. Allow us to compare apples to oranges, however, and the Portable SSD T5 and its next-generation USB 3.1 Gen 2 interface make it the king of portable SSDs in our testing.

Even so, our testing can't account for Adata's durable outer shell, and we doubt the Samsungs could stand up to the same level of abuse that the SD700 likely can. The combination of speed and apparent durability the SD700 offers could be more appealing than speed alone to some users.