YAPT (yet another performance test) is a benchmark recommended by a pair of drive manufacturers and was incredibly difficult to locate as it hasn't been updated or used in quite some time. That doesn't make it irrelevant by any means though, as the benchmark is quite useful. It creates a test file of about 100 MB in size and runs both random and sequential read and write tests with it while changing the data I/O size in the process. The results are a good look at overall drive performance.
This is not a 4k aligned test. We keep it around because it helps amplify and spread out differences in controller and flash speed, as well as demonstrating how the SSD responds to misaligned or sub-4k writes. The spread is fairly obvious in sequential writes, and in random writes we see the 128GB 850 Pro overpowering every other competing model / capacity in this test. An impressive showing to say the least!