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.
Disclaimer: YAPT is not a 4K aligned test. This causes the Red (and even the VelociRaptor in some places) to see a considerable performance hit on random access tests. The newest models of the Red appear to be hit harder than others here, as I suspect further optimizations have been made that more heavily rely on 4k alignment. While *most* NAS devices will properly align their data to 4k boundaries, it may be worth double checking just in case. If they don't, a firmware should be available to correct this issue for newly created arrays.