SAS SSD Drives: 12Gb/s vs 24G SAS, Bay Fit, Part Numbers and UK Prices

What a SAS SSD is: 12Gb/s SAS-3 and 24G SAS-4

The maker documents for the drives on this page cover two generations. WD's Ultrastar DC SS530 and Seagate's Nytro 3000 series are 12Gb/s SAS drives with dual ports. KIOXIA's PM7-R is a 24G SAS drive, which KIOXIA lists as SAS-4, with single or dual port support. KIOXIA's technical brief says each SAS-4 lane runs at 22.5 Gb/s, effectively doubling the earlier rate, and that SAS SSDs and hard drives typically use two or four lanes.

The newer drives are built to sit in older systems. KIOXIA calls 24G SAS backwards compatible with SAS-3 at 12 Gb/s, SAS-2 at 6 Gb/s and SATA at 6 Gb/s, and lists 12.0 Gbit/s among the PM7-R's interface speeds. On that basis a PM7-R in a 12Gb/s SAS system runs at the system's speed rather than its own; check the controller's documents before you count on more.

SAS SSD 2.5-inch: will it fit your bay and controller

KIOXIA's brief makes two points about mixing interfaces. A SAS backplane also supports SATA drives, so SATA and SAS drives can share bays on SAS infrastructure, and SATA SSDs or hard drives can be replaced with SAS SSDs without any changes. Both statements are about a system that already runs SAS.

The reverse is the case to watch. We have not found a document stating that a SAS SSD works in a SATA-only port or backplane, so do not plan on it. The SS530 is a 2.5-inch, 15 mm drive and the PM7-R a 2.5-inch drive, so the bay itself must take that size, and the SAS vs SATA page compares the two interfaces in more depth.

SAS SSD drives on Amazon.co.uk: the part numbers

WD's Ultrastar DC SS530 SAS SSD sheet was produced in July 2018 and revised in September 2019. It lists 3.2TB in two endurance classes: WUSTM3232ASS20x at 10 drive writes a day and WUSTR6432ASS20x at 3, where the final x denotes the encryption level. So a size of 3.2TB alone does not tell you the class. The SS530 listing we track carries 0B40354 and 3.2TB in its title, and we have not found a WD document that maps 0B40354 to a model number, so ask the seller which class the drive is before you buy.

KIOXIA's PM7-R brief lists the self-encrypting 3,840GB model as KPM7VRUG3T84, the part number on a UK listing, and describes the drive as read intensive at 1 DWPD. A Seagate Nytro 3350 listing carries XS15360SE70045; Seagate's Nytro 3000 sheet covers the series' 12Gb/s dual-port design and its three endurance options. Other Seagate listings carry 1200.2 part numbers, ST800FM0173 and ST3840FM0053, and we have not found a Seagate document for that series, so this page prints no specification for them.

Choosing an enterprise SAS SSD: three questions

We have not found a common test across these makers that would support a best pick, so we do not rank SAS SSDs. The makers' own figures are still enough to narrow the choice.

• Which SAS generation does your controller run? A 24G drive such as the PM7-R lists 12 Gb/s among its speeds, while a 12Gb/s drive such as the SS530 lists 6 and 12 Gb/s.
• How much do you write each day? The SS530 is offered at 10, 3 and 1 drive writes a day; the PM7-R is rated at 1 DWPD.
• How much capacity per bay? The SS530 range stops at 15.36TB, the PM7-R range reaches 30.72TB.

Used and refurbished SAS SSDs can appear in the table beside new ones, each row marked with its condition. A used SSD has spent part of its rated writes, so ask the seller what the drive reports about wear, and match the part number to the endurance class before you pay. The refurbished SAS drives page covers buying used SAS hard drives.

SAS SSD price on Amazon.co.uk

The SAS table holds 2 listings right now. Prices are pounds sterling inc VAT, sorted per TB, and each row shows its condition. The table takes enterprise SSD listings we record as SAS, and leaves out M.2 titles.

Before you press Buy on Amazon, check the generation, the endurance class and the drive height in the listing against your system. The enterprise SSD page sets SAS beside SATA and NVMe, and the SAS vs NVMe page compares those two interfaces directly.

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.