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TR RoboBench — Real-world transfers
RoboBench trades synthetic tests with random data for 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.

Read speeds are up first. Click the buttons below the graphs to switch between one and eight threads.

The SM951 battles for podium spots with the Intel PCIe drives. It's well ahead of the XP941 and every other SSD we've tested.

That trend continues with writes. The SM951 beats the 750 series with eight threads in flight, but it's a little slower in the single-threaded tests. Either way, the drive performs better than not only its predecessor, but also the entire SATA field.

There are no surprises in RoboBench's copy tests. Again, the SM951 hangs out with the Intel PCIe drives at the front of the pack.

RoboBench only reports the overall transfer rate for each run, so we can't check for slowdowns during the test. The run-to-run scores show no evidence of throttling, though. The scripted test sequence also reboots before each run and then waits a couple minutes for the OS to finish loading. That pre-programmed delay, coupled with the fact that the SM951 completes some of the RoboBench tests in as little as seven seconds, may keep thermals within acceptable bounds.