Because the throughput of these hard drives will be limited by the used NAS and the network connection we do not primarily look at the speed here, but at the elements that are important for this segment: noise levels and power consumption. Therefore it is a good idea to bear this is mind when looking at the benchmark results: faster in the benchmarks does not necessarily mean that a hard drive will be faster in a NAS.
While the Western Digital Red drives are the slowest pretty much everywhere in the test, they are still interesting for use in a NAS because of their noise levels and price. The Seagate models perform a lot better, although they produce so much more noise that we would not recommend them. The WD Red Pro shows very solid performance, especially when it comes to the amount of operations per second, but is too expensive and produces too much noise. Unfortunately the HGST drives are not quiet enough in order to receive our recommendation. The Red-drives receive an Excellent Choice Award, with the exception of the 4 TB category, where that price goes to the IronWolf.
The new Seagate IronWolf-drives mostly perform very well: they are at the top of nearly every benchmark. That said, you will probably not notice a lot of difference in practice in a NAS. The noise levels are also quite high. An exception to this is the IronWolf 10 TB, which is inaudibly quiet in idle. It is also consumes less power than the other models in this series. Both advantages are probably due to the application of helium. It is not more expensive in terms of price per gigabyte compared with the Red-drives, which is certainly impressive considering its capacity. Therefore, this IronWolf also receives an Excellent Choice Award.
With all these conclusions comes the note that we cannot make any statement about what is actually the most important aspect of hard drives, namely the durability. Therefore it is recommended to always create a backup of important data.