AS SSD is a benchmark that uses non-compressible and completely random data. Usually, we run this benchmark on SSDs to remove the advantage of the SandForce-driven drives, but it’s still a good benchmark to see how mechanical hard disks deal with non-compressible data.
Sequential read and write speeds of the WD Black 4TB was pretty impressive as it was markedly quicker than even the old 300GB VelociRaptor drive and also the WD Black 1TB drive. This was also true for its copy speeds in the Copy Benchmark, which simulated copy workloads. However, on the more intensive 4k and 4k, 64 thread workloads, the VelociRaptor drives gained the upper hand.