20TB Hard Drive Prices: Generations Compared for UK Buyers

20TB hard drive price: enterprise drives on Amazon.co.uk

This table holds the enterprise-class 20 TB offers we track as in stock on Amazon.co.uk: 6 at the last price check. The lowest is £31.77/TB, on Seagate Technology Exos X20 (used) at £635.36, in pounds sterling inc VAT.

Check the Interface column first if you have a SAS backplane; the SATA and SAS mix changes with stock. The Recording column names a technology only where a maker document backs it; otherwise it says not sourced.

We compare six enterprise 20TB hdd generations from their data sheets

Many generations overlap at 20 TB. Seagate's X20, X22 and X24 sheets all list a 20 TB model, Western Digital's HC560 reaches it on nine disks, and Toshiba offers it in both MG10 and MG11. W/TB below is our own division of each data-sheet idle figure by 20.

In SATA, no later Seagate generation lowered idle power at 20 TB. The X24's 6.3 W sits 0.9 W above the 5.4 W that both the X20 and X22 sheets give. Seagate prints that 6.3 W at every X24 capacity, so a 20 TB X24 idles like its 24 TB sibling. Over the 8,760 power-on hours Seagate's sheet counts in a year, the working is 0.9 W x 8,760 h = 7,884 Wh, or about 7.9 kWh per drive. Multiply by your tariff and your drive count to see whether that gap matters to you.

Nor did the top speed move: the X20 and X24 sheets share a maximum sustained rate of 285 MB/s at the outer diameter. What the later Seagate sheets do add is cache, 512 MB against the X20's 256 MB. Toshiba's SATA figures, 4.38 W on the MG10 and 4.35 W on the MG11, sit below every Seagate and WD figure in the comparison, though a data-sheet number says nothing about the price of the row you are looking at.

20TB hard drive Seagate part numbers: the trap in the digits

The digits in a Seagate 20 TB model number do not tell you the interface, and two pairs prove it. Change the final letter and the interface flips with the generation:

• ST20000NM007D is an X20 with SATA; ST20000NM007H is the X24-family model with SAS.
• ST20000NM002D is an X20 with SAS; ST20000NM002H is the X24-family model with SATA.
• ST20000NM001H (SATA), ST20000NM005H (SAS) and ST20000NM006H (SAS) are the self-encrypting versions on the same sheet, the last of them SED-FIPS.

On these sheets the final letter tracks the generation: D for X20, E for X22, H for X24. Match the whole string in the Part number column against the list above, because a listing title that only says Exos 20TB settles neither point. The Seagate Exos family page takes the range beyond this capacity.

20TB hdd internal: what SATA and SAS change on one data sheet

Seagate's Exos sheet DS2046.1 lets you compare the two interfaces at the same 20 TB without a generation muddying it. SATA models have a single port and SAS models have two. SATA lists 512 and 4,096 byte sectors, whereas SAS adds 520 and 528 on the 512e side, and 4,160 and 4,224 on the 4Kn side. SAS costs little extra at idle, 6.5 W against 6.3 W, but more under load: maximum operating power is 9.8 W and 8.2 W for SAS, 8.9 W and 7.1 W for SATA, measured on 4K random reads and writes. The sheet rates both at 2,500,000 hours MTBF and 0.35% AFR, with a 5-year limited warranty.

Workload is harder to compare. The HC560 and MG10 are both rated at 550 TB a year, but we have not found a workload rating in the X20 or X24 sheets we opened, so we print none for them. Ports and sectors are only part of how SAS and SATA differ, but they are what these sheets let us state.

How long a 20TB rebuild takes at the very best

A replacement drive has to be written from end to end, so the sum needs only a capacity and a rate. Seagate counts a terabyte as one trillion bytes, so 20 TB is 20,000,000,000,000 bytes. Divide by each maker's stated sustained rate:

• Exos X20 and X24 at 285 MB/s: 20,000,000,000,000 / 285,000,000 = 70,175 seconds, or 19.5 hours.
• Ultrastar HC560 at 291 MB/s: 20,000,000,000,000 / 291,000,000 = 68,729 seconds, or 19.1 hours.
• Toshiba MG11 at 281 MiB/s, which is 294,649,856 bytes per second: 20,000,000,000,000 / 294,649,856 = 67,877 seconds, or 18.9 hours.

Treat these as floors, not forecasts. Each holds a maximum rate across the whole drive with nothing else touching the array, and a real rebuild will not do that.

We have not found a maker document stating a typical RAID rebuild rate, so this page offers no hours estimate beyond the floors. For your own figure, divide 20,000,000 by the MB/s your controller reports during a rebuild, then divide by 3,600.

20TB hdd NAS drives: a separate class

These 8 offers are NAS-class drives, tagged apart from the table at the top, and no row here counts as enterprise. The lowest is £35.75/TB.

For a 20TB NAS build, the class label alone does not prove a drive works in your box. We have not opened a maker document on NAS support for this capacity, so we name no compatible pairing here, in either direction. Take the full part number to your NAS maker's own drive list, and confirm the interface and bay form factor while you are there.

20TB hdd surveillance, desktop and other classes

Surveillance class comes next, 2 offers from £39.99/TB. An application list is not a class label: Toshiba lists video surveillance among the MG11's uses and the X20 and X22 sheets list centralised surveillance, yet those stay enterprise drives and are not filed here.

The next tables hold 1 other-class and 1 desktop-class offers. We hold no data sheet for these classes on this page, so we state no power or rating.

20TB hard drive refurbished: reading the Condition column

The Condition column reads New or Used and has no separate refurbished value. If you want a refurbished 20TB drive, judge any Used row against the New rows above it, on the same part number where you can, because a drive from an older generation can look cheap for reasons that have nothing to do with its condition.

Keep two protections apart. Seagate backs the X20 with a 5-year limited warranty, but we have not found a Seagate document saying whether that warranty follows a used unit bought from a marketplace seller, so ask before you pay. Separately, GOV.UK tells businesses they must offer a full refund if an item is faulty, not as described or does not do what it is supposed to. That duty falls on a business seller and is not a maker's warranty.

Used stock at other capacities is the subject of refurbished enterprise hard drives, which is not limited to 20 TB.

20TB hard drive price history: what we can and cannot show

We have tracked Amazon.co.uk prices since 5 November 2026, but the chart here is deliberately broad: cheapest and median £/TB across every in-stock hard drive we follow, all capacities and conditions together, not 20 TB alone. Lines move when listings come and go, so a shift in the chart is not a price change on any drive, and we derive no percentage from it. We do not print the past price of any single listing. The price per TB ranking sets 20 TB against the rest of the field today.

Price tracking on Amazon.co.uk began on 5 November 2026. A chart needs at least two complete days, so there is nothing to plot yet.