Seagate has updated their flagship capacity options for the retail HDD market with the availability announcement for two new hard drives today - the Exos X20 and IronWolf Pro 20TB. These two models join the recently-released Western Digital WD Gold 20TB and Ultrastar HC560 to round out the 20TB hard drives currently available for retail purchase.

The Exos X20 comes with SATA as well as SAS 12Gbps interface options, and includes SED (self-encrypting drive) models while the IronWolf Pro is SATA-only (similar to previous generations). The Exos X20 has a workload rating of 550 TB/yr, while the IronWolf Pro version is rated for 300 TB/yr. A detailed comparative summary of the different specifications of the two new drives and how they stack up against the Western Digital offerings is provided in the table below. Only the SATA options of the Exos X20 and the Ultrastar HC560 are being considered for this purpose. The two model numbers corresponding to these are for the SED and non-SED (standard) options.

2021 Retail 20TB HDDs - Comparative Specifications
Exos X20 20TB
IronWolf Pro 20TB
Western Digital
WD Gold 20TB
Western Digital
Ultrastar HC560
Model ST20000NM007D
ST20000NM000D (SED)
ST20000NE000 WD201KRYZ WUH722020ALE6L1 (SED)
Recording Technology Conventional Magnetic Recording
Conventional Magnetic Recording with Energy-Assist
RPM 7200 RPM
DRAM Cache 256 MB 512 MB
Helium-Filling Yes
Sequential Data Transfer Rate
285 MB/s 269 MB/s
MTBF 2.5 M 1.2 M 2.5 M
Rated Annual Workload 550 TB 300 TB 550 TB
Acoustics Idle 28 dB 20 dB
Seek 30 dB 32 dB 36 dB
Power Consumption Random read/write 9.4 W / 8.9 W (100R/100W @ QD16) 9.4 W / 8.9 W (100R/100W @ QD16) 7 W
(50R/50W @ QD1)
Idle 5.5 W 5.4 W 6 W
Warranty 5 Years 5 Years
(3 years DRS)
5 Years
Pricing $670 $650 $680 $700

The IronWolf Pro model also has a 1W standby / sleep-mode power consumption rating that could prove useful in NAS units that are subject to constant 24x7 traffic. The idle acoustics are at the higher end for the Seagate models, but the seek numbers make up for it. Unfortunately, we do not have a way to compare the power consumption numbers based on the datasheets, as the workloads used for the characterization are different between the two vendors. That said, the idle numbers lean again towards the Seagate models.

It must be noted here that the list price premium for the WD models can be accounted for by the use of OptiNAND technology in the WD Gold and Ultrastar HC560. We reached out to Seagate on the use of HAMR in the new models, and surprisingly, Seagate indicated that the two new hard drives being introduced to retail today do not use heat-assisted magnetic recording.

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  • GTRagnarok - Thursday, December 2, 2021 - link

    Why have different hard drive makers remained equals for so many years with regards to capacity? One comes out with the next highest capacity and the other follows shortly.
  • shabby - Thursday, December 2, 2021 - link

    That's how collusion works...
  • QChronoD - Thursday, December 2, 2021 - link

    Probably also because the largest storage purchasers are going to be running the drives in large arrays, so that would require every drive to be the same size. Otherwise they're going to be paying extra for larger drives whose space they wouldn't be able to use. Everyone making drives that have the same capacity is good for the customer being able to mix brands, and also good for the seller since they won't be automatically disregarded due to being too small or have to drop prices if their drive is bigger.
  • SigmundEXactos - Thursday, December 2, 2021 - link

    Because 3rd party companies create the platters which allow higher densities. So it's not in full lockstep, but they're close.
  • Samus - Thursday, December 2, 2021 - link

    Because Showa Denko
  • meacupla - Thursday, December 2, 2021 - link

    Probably because it's really hard to develop a new technology, and instantly hit the maximum theoretical density in a single generation.

    Also, that is not true in the 2.5" market.
    WD doesn't offer anything over 2TB, Toshiba only offers up to 4TB, and Seagate offers up to 5TB.
  • name99 - Thursday, December 2, 2021 - link

    That (2.5" sizes) is admittedly frustrating, but I think it reflects the market.
    - in-device drives (think laptops) tend to be maybe up to 2TB or to be SSDs
    - backup and large storage (media or whatever) tend to be 3.5"
    - portable moving data from here to there can either fit in 5TB (or a lot less!) or the user has moved on to SSD.

    There's just not much of a market anymore for that form factor, as a spinning disk, in leading edge sizes.
  • meacupla - Thursday, December 2, 2021 - link

    The 2.5" in capacities higher than 2TB wouldn't fit in laptops anyways.
    These 4/5TB 2.5 drives are meant for mITX type desktops, and mini NAS, like synology DS419slim and DS620slim.

    However, since we now have 18TB and 20TB 3.5" drives, I don't know if 5TB 2.5" offers a good alternative for NAS setups.
    Like, I can see this comparison being something like a 6x 5TB 2.5" drives in RAID5 vs. 2x 20TB 3.5" drives in RAID1 situation, and the only savings had is weight.
  • jeremyshaw - Saturday, December 4, 2021 - link

    Aren't all of those high density 2.5" HDDs SMR, making them inadvisable for RAID setups?
  • boozed - Friday, December 3, 2021 - link

    Ahh great it's AT's next recommended consumer HDD!

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