The drive is brand new and has the latest firmware installed. Let’s start our tests. The advertised "sustained transfer speed" is around 262ΜΒ/sec. The AJA System Test gives a rough idea of the drive's performance. We got around 243MB/sec reading/writing speed.

The ATTO Disk benchmark gives us more details:

Above 8K files we got around 258mb/sec reading and 258mb/sec writing speeds. The ATTO Disk Benchmark v4.00 showed slight lower speeds.

Passing to the CrystalDiskMark software we got results from 3.01, 6.02, 7 and the latest 8.01 versions. The performance in all cases is similar for the sequential reading/writing speed.

Our test with IOMeter doesn’t give us much high score, since traditional HDDs are not very good with a lot of small files.

- Conclusion

The WD UltraStar DC HC Series comes with a legend reability and performance numbers for entousiast, enterprise users. There are several importand and special features that are not found in other enterprise HDD (like HelioSeal® design and Energy-Assisted Magnetic Recording technology). While WDC offers also Red Pro and Gold series for our NAS server we chosen the UltraStar series due to its high performance and unique features. The performance was very good and in most cases according to the specifications. We don't expect much performance differences between Gold and UltraStar series, maybe in future we would be able also to test the Gold 16TB series as well. Noise levels even after hard testing were minimal, a good surprise for us and as for running temperature we hardly saw above 40 Celsius (open testbed) numbers.

The WDC UltraStar DC HC550 series comes with 5 years of limited warranty to keep end users worry free. Overall we feel that this product is very solid and we have no problem suggesting it for users who wish to upgrade their storage NAS needs with a big and fast HDD. Did we also mentioned that this product probably would cost even less than the Gold series? :-)