Exos X24 Datasheet: Part Numbers at 24, 20, 16 and 12 TB, With X18 and X20 Compared

Exos X24 datasheet: SATA and SAS part numbers

Seagate's X24 sheet, DS2080-2307US, linked under sources, splits the generation into two tables with the same four sizes: SATA 6Gb/s on page 2 and SAS 12Gb/s on page 3. This grid joins them, in the sheet's order from 24 TB down. The sheet labels the first row Standard Model - Seagate Instant Secure Erase (ISE), shortened here to standard (ISE).

Three features of this grid are worth checking against any order. The SATA SED-FIPS row is empty at all four sizes, so that option means SAS. Three of the four SAS SED-FIPS numbers end 006H, and the fourth, at 12 TB, is ST12000NM009H. And each standard (ISE) SATA number differs from its SED sibling by a single digit: ST24000NM002H against ST24000NM001H.

Seagate's sheet describes the generation's data protection as 'Seagate Instant Secure for safe, affordable, fast, and easy drive retirement'. That is the maker's description of a feature. This page has no test of it and takes no view on whether it meets a particular security policy.

Exos X24 24TB, 20TB, 16TB and 12TB: one set of figures

The sheet's columns do not separate these four sizes on the rows below. A 12 TB drive is listed with the same cache, the same transfer rate, the same power figures and the same 685 g as a 24 TB drive. Interface is what moves the numbers: 0.2 W at idle, then 0.9 W on random read and 1.1 W on random write at maximum operating power.

That is Seagate's statement about the product, not about a particular seller or a used or recertified unit.

A flat idle figure changes how capacity should be weighed. Our arithmetic from the sheet, at idle only: 6.3 W across 24 TB is about 0.26 W per TB, across 20 TB about 0.32 W, across 16 TB about 0.39 W and across 12 TB about 0.53 W. On paper, the smallest X24 takes twice the idle watts per terabyte of the largest. That is not a measured running cost, and it leaves out load, cooling and anything your enclosure adds.

SAS lists two more 512e sector sizes than SATA, so check what your controller expects. A footnote to the standard (ISE) row says FastFormat models ship in 512e, and that switching to 4Kn by the FastFormat routine deletes all data.

Exos X24 prices on Amazon.co.uk

The Exos X24 table below holds 3 listings, in pounds inc VAT, each with its condition, under titles the sellers wrote, so settle capacity and interface from the part number and the grid above. A used row is not proof of a factory-recertified drive.

If an Amazon title calls ST24000NM002H SAS, the sheet prints it as SATA, and we go by the sheet. The sort is per TB and mixes every size, so narrow to your capacity and interface before comparing. The filter behind this table leaves out one number that is not on the sheet, and others could still appear. If a listing gives no part number, ask for it before you press Buy on Amazon.

One size in other generations and makers is a different question. Seagate Exos 24TB stays with the one capacity across Seagate's lines, and 24 TB hard drives takes the wider view. Seagate Exos has the range.

Exos X24 vs X20: what 512 MB of cache comes with

Twice the cache and four more terabytes at the top are the headline changes. Sustained transfer stands still. The idle figure rises by 0.9 W on SATA and 0.7 W on SAS, and the drive gains 15 g.

Divide by capacity and the top models come out almost level: 6.3 W at 24 TB is about 0.26 W per TB and 5.4 W at 20 TB about 0.27 W, on SATA. The two generations part at 20 TB itself, where X24's figure works out at about 0.32 W per TB. So if 20 TB is what you need, the sheets favour X20 on idle and X24 on cache; if you can use 24 TB, the idle argument mostly disappears. Exos X20 prints the older generation's numbers in full.

Exos X24 vs X18: how far the sheets have moved

The X18 sheet stops at 18 TB and the two share 16 TB and 12 TB. Top model against top model, the X24 sheet adds 6 TB of capacity and 15 MB/s of sustained transfer over the 18 TB drive, for 1.0 W more idle power on SATA, 0.9 W more on SAS and 15 g. At 16 TB, where the capacity matches, the X24 lists 6.3 W against the X18's 5.1 W on SATA and 6.5 W against 5.5 W on SAS, which is 1.2 W and 1.0 W more.

Per terabyte the newer drive still leads at the top: about 0.26 W per TB at 24 TB against about 0.29 W at 18 TB, on SATA. Move down the X18 line and weight also falls, to 650 g at 14 TB, whereas X24 keeps 685 g at every size. So a small X24 is the same physical weight on the sheet as its largest sibling. At 16 TB the standard SATA numbers are ST16000NM002H and, on Exos X18, ST16000NM000J.