Seagate Exos 20TB Reference: X20 or X24, and What Recertified Changes

Seagate Exos 20TB part numbers on the two sheets

Two data sheets carry this size. On the X20 sheet it is the top capacity, above 18 TB, and Seagate markets it there as offering the highest capacity available when that document appeared. On the X24 sheet the same size ranks under 24 TB, with 16 TB and 12 TB below it. Both print encrypting variants beside the standard models.

Anyone searching seagate exos 20tb st20000nm007d wants the X20 SATA standard model, and that is what the sheet makes it. Watch the string that looks closest. ST20000NM007H shares every digit, yet X24 prints it under SAS, so a single letter moves you to a different generation and a different interface.

Seagate Exos 20TB SATA or SAS: what the X20 sheet separates

Beyond the connector, X20 draws further lines between its models at this capacity. Protection Information (T10 DIF) reads yes under SAS and shows a dash under SATA. SATA has a single port and SAS dual ports. Average idle is 5.4 W on SATA and 5.8 W on SAS. If your stack depends on T10 DIF, that rules out ST20000NM007D. The X24 sheet we hold has no T10 DIF row, so we make no claim for X24; confirm with Seagate or the seller.

Seagate Exos 20TB X20 vs X24: cache, idle power and ratings

Speed does not separate these two. Both print 285 MB/s, so the higher generation number buys no extra sustained transfer here, and both print 168/550 random IOPS. The differences we print here are cache, where X24 doubles X20's 256 MB, idle draw, 0.9 W higher per SATA drive on X24, operating power and weight. We have not tested either, so these are Seagate's ratings rather than results of ours.

Same on both sheets: a 5-year limited warranty, a 2.5M-hour MTBF rating and 8,760 power-on hours a year.

Seagate Exos 20TB recertified: numbers and near misses

Seagate's Factory Recertified Hard Drive sheet prints three numbers at this size on a SATA 6 Gb/s table: ST20000NM002C, ST20000NM004C and ST20000NM003C. Its support page names ST20000NM002C with a 6-month limited warranty. The programme page says these products are certified to meet Seagate factory performance standards, and that specifications and warranties for prime drives do not apply to them.

Mind the last character. ST20000NM002C is on the recertified list, ST20000NM002D is the X20 SAS model and ST20000NM002H is the X24 SATA model. A slip here moves you between a 6-month and a 5-year warranty statement, and between SATA and SAS. We have not found a Seagate document defining that letter, so match the full string exactly as printed.

Both new sheets state 8,760 power-on hours a year and 10E15 read errors, where the recertified sheet states 2,400 and 10E14, and Exos refurbished drives sets out that gap in full along with the serial, label and drive checks. We have not found a document tying a recertified 20 TB to X20, X24 or any other new model.

Seagate Exos 20TB price and refurbished listings on Amazon.co.uk

Any row here is filed under Exos at 20 TB, and the Condition column shows whether we class it as new or used. Prices are pounds sterling inc VAT, lowest per TB first, as at 14 November 2026, 00:39 UTC. Where a product name shows a part number, compare it with the grid at the top. Where it does not, get the number from the listing or the seller, because capacity alone will not tell X20 from X24.

A used label is not proof of Seagate factory recertification. Any talk of renewal or recertification in a title comes from the seller, and even a number that appears on Seagate's list does not establish that Seagate reworked that particular unit. Before you press Buy on Amazon, ask who handles a warranty claim.

Where the Interface column reads not stated, the part number settles it. Drives from other makers at this size are on 20 TB hard drives, and the SAS question gets its own treatment under 20 TB SAS drives.

In-stock alternatives

None of these is the product this page covers: they are what is in stock on Amazon.co.uk beside it right now. Each row says why it is listed. Check the interface, form factor and part number against your system before buying.

A recertified 20 TB and your rights: the 30-day limit

Part 1 of the Consumer Rights Act 2015 applies where there is an agreement between a trader and a consumer. If that describes your purchase, goods supplied by description must match it, so a listing promising a recertified 20 TB is judged against what turns up. The short-term right to reject ends after 30 days, counted from the first day after ownership has passed and the goods have been delivered, which is why testing a large drive soon after delivery matters. A purchase from a private individual is not a trader-to-consumer agreement.

That statutory limit and the sheet's 6-month limited warranty are different things from different sources. Citizens Advice says warranties and guarantees add to your legal rights, so holding one does not cancel the other.