WD Ultrastar SATA HDD: Which Generation at Each Capacity, from 4TB to 26TB

WD Ultrastar SATA hdd prices on Amazon.co.uk

This table holds 31 listings right now. Lowest price per TB: £22.50/TB, pounds sterling inc VAT. New and used drives share one table, and older HGST-branded Ultrastar He listings sit in it too, since the line is WD's. Some of those older listings give no capacity, and their capacity cell shows a dash; the model number on the row is the better guide.

A cheap price per TB on a used 4 TB or 6 TB drive and a higher one on a new 18 TB drive are not the same purchase. Before you compare rows, decide the capacity you need and whether you will accept a used drive, then use the guide below to check that the model number on the listing is the drive you expect.

WD Ultrastar 4TB and 8TB SATA: HC310, HC320 or HC510

At the small end the choice is between three older generations. The HC310 covers 4 TB and 6 TB, with 512e SATA models on the HUS726TxTALE6yz pattern and a 512n SATA model, HUS726T4TALA6yz, at 4 TB only. WD states one SATA idle figure for the family, 5.9 W, which by our division is about 0.98 W/TB at 6 TB.

At 8 TB two generations meet, and they are not alike. The HC320 SATA models, HUS728T8TALE6L1 and HUS728T8TALE6L4, idle at 7.4 W. The HC510, which covers 8 TB and 10 TB, idles at 5.0 W in SATA. For a server that runs all day, the HC510 is the lower-power 8 TB Ultrastar on paper by 2.4 W, our subtraction, so check which of the two a listing is before you compare prices.

WD's keys decode the suffix. On the HC310 and HC510 keys, E6 marks a 512e SATA model; the HC310 key gives A6 for 512n SATA, and the HC510 key gives N6 for 4Kn SATA. So ALE6, ALA6 and ALN6 in a model number are all SATA drives, in three different sector formats.

WD Ultrastar 10TB, 12TB, 16TB and 18TB SATA, and above

• 10 TB: HC510.
• 12 TB: HC520.
• 14 TB: HC530, SATA models WUH721414ALE6L1 and WUH721414ALE6L4, or the HC550.
• 16 TB and 18 TB: HC550, whose SATA models end ALE6L1 or ALE6L4.
• 20 TB: HC555, or HC560 with SATA models WUH722020ALE6L1, WUH722020ALE6L4, WUH722020BLE6L1 and WUH722020BLE6L4.
• 22 TB: HC570, WUH722222ALE6L1 and WUH722222ALE6L4 (WD part numbers 0F48154 SED and 0F48155 Base SE), or HC580, WUH722422ALE6L1 and WUH722422ALE6L4.
• 24 TB: HC580, WUH722424ALE6L1 and WUH722424ALE6L4, or HC590, pattern WUH722624ALxxyz.
• 26 TB: HC590, pattern WUH722626ALxxyz.

The HC570 and HC560 also print short WD part numbers, such as 0F48154 and 0F38754. Those carry no interface code, so match them to the sheet as whole numbers. The HC590 sheet prints one pattern per capacity for both interfaces, so there the interface sits in the characters WD writes as xx.

Idle power per terabyte across SATA Ultrastars

Idle power per drive barely moves from the HC510 to the HC590, between 5.0 W and 6.1 W, while capacity more than doubles, so the watts per terabyte fall by more than half. The two small generations sit at the top of the table: the HC310 at 6 TB and the HC320 at 8 TB both come out near 1 W/TB.

On most of these sheets the SATA version idles below its SAS twin: HC310 5.9 W against 7.0 W, HC520 5.0 W against 6.1 W, HC590 5.6 W against 5.9 W. The HC560 is the exception, printing 6.1 W for its ALE6 SATA models and 6.1 W for SAS; its BLE6 SATA models are lower at 5.8 W.

20TB SATA Ultrastar: HC555 or HC560

The HC560 is slightly faster on paper and the HC555 more frugal, idling 0.8 W below the HC560's ALE6 models by our subtraction. The HC555 sheet also prints SATA idle efficiency at smaller sizes: 0.29 W/TB at 18 TB, 0.33 at 16 TB and 0.38 at 14 TB. For the HC560's own listings, see Ultrastar DC HC560; for 24 TB, WD Ultrastar 24TB.

What a SATA Ultrastar gives up, and what it gains

• Lower idle power on most generations, as the table above shows, with the HC560's ALE6 models the one tie.
• Sector formats: on the HC320 the SATA model's 512e format is 512 bytes only.
• Controllers: Seagate's support note on the interface says SATA drives may be plugged into SAS controllers, so a SATA Ultrastar is not limited to SATA-only machines.

If the drive ports in your home server, NAS or workstation are SATA, the SATA Ultrastar is the version to shortlist. We have not found a port row on the WD sheets used here, so if dual-path connection matters, ask WD or the seller. For the SAS side of the family, with its own model numbers and sector formats, see WD Ultrastar SAS, and for the interface itself, SAS vs SATA.

Used WD Ultrastar SATA drives: who you buy from matters

Used drives appear in this table beside new ones, and the seller decides what protection you get. When you buy from a trader as a private buyer, GOV.UK's guidance for traders says they must offer a full refund if an item is faulty, not as described or does not do what it is supposed to. That guidance is written for businesses, so it does not describe a sale between two private individuals.

The Consumer Rights Act 2015 counts you as a consumer when you act wholly or mainly outside your trade, business, craft or profession, and your short-term right to reject a faulty item from a trader lasts until the end of 30 days. Fill and test a used drive within that time. For refurbished Ultrastars in both interfaces, see refurbished WD Ultrastar.