Exos generation comparison

Seagate Exos X16 vs X18 vs X20 vs X22 vs X24

Exos generations overlap heavily in retail listings. This comparison shows what changed from X16 through X24 and helps you decide whether an older model is still a good buy at its current price.

Exos specifications reviewed August 5, 2026 X16 through Exos M Generation, interface and model verification required

Quick answer

X24 is the cleanest current-generation choice for 12TB, 16TB, 20TB and 24TB, with 512MB cache and current channel positioning. X16, X18, X20 and X22 can still offer excellent value, but only when the exact model, interface, condition and warranty source are verified.

X16 ceiling16TBCommon older generation

X18 ceiling18TB270MB/s representative maximum

X20 ceiling20TB285MB/s representative maximum

X22 ceiling22TB512MB cache generation

X24 ceiling24TBCurrent CMR channel family

Exact model data

Representative standard SATA models by generation

Capacity	Model	Generation	Interface	Sector format	Security	Recording	Cache	Max sustained	Status
16TB	`ST16000NM001G`	Exos X16	SATA	512e/4Kn FastFormat	Standard	CMR	256MB	261MB/s	Older generation
18TB	`ST18000NM000J`	Exos X18	SATA	512e/4Kn FastFormat	Standard	CMR	256MB	270MB/s	Older generation
20TB	`ST20000NM007D`	Exos X20	SATA	512e/4Kn FastFormat	Standard	CMR	256MB	285MB/s	Older generation
22TB	`ST22000NM001E`	Exos X22	SATA	512e/4Kn FastFormat	Standard	CMR	512MB	285MB/s	Older generation
24TB	`ST24000NM002H`	Exos X24	SATA	512e/4Kn FastFormat	ISE	CMR	512MB	285MB/s	Current channel generation

Representative models are used for generation comparison. Every generation also has interface and security variants that require exact-model verification.

Live catalogue

Current offers across Exos X16 through X24

Only fresh, exact-model products returned by Amazon's new-condition search are eligible. Featured prices are shown when Amazon exposes them; products with no buy box are shown as buying options. Generation, interface, capacity, security class and exact model are enforced.

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Checking the current Cloudzat catalogue…

Interactive decision tool

Compare two Exos generations

Choose representative exact models to compare capacity, cache, transfer speed, interface and current status.

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X16 remains a common value option

X16 established 14TB and 16TB enterprise capacities and remains common in used and recertified markets. New-stock value depends on the exact warranty and price.

X18 raised capacity and sequential speed

X18 brought 18TB models and representative sustained transfer rates around 270MB/s while retaining 256MB cache on common models.

X20 reached 20TB

X20 extended the family to 20TB and published transfer rates up to 285MB/s on key models. It remains widely available in home-server and NAS markets.

X22 moved to 512MB cache

X22 brought 20TB and 22TB models with 512MB cache. It can be attractive when 22TB fits the array plan better than 20TB or 24TB.

X24 is the current conventional CMR line

X24 covers 12TB, 16TB, 20TB and 24TB and provides separate SATA ISE, SATA SED and SAS configurations. It is the simplest current reference point before moving to Exos M.

Newer does not guarantee better value

A discounted older-generation model may have a lower cost per terabyte. Compare price, warranty source, acoustics, power and array uniformity, not the generation name alone.

Avoid mixing interfaces and sector formats

An array can only use drives the controller understands. Mixing sector formats or installing SAS in a SATA-only chassis can prevent detection or complicate replacement.

Compare exact offers, not family averages

Cloudzat filters Amazon results to exact models and new condition, then links to the existing Exos price engine for broader live pricing.

How Cloudzat evaluates Exos drives

Cloudzat attaches generation, interface, sector format, security class, recording technology, cache, transfer rate and warranty only to an exact model. Exos X16, X18, X20, X22, X24 and Exos M remain separate, as do IronWolf Pro and WD Gold comparison products. This prevents a SATA listing from inheriting SAS specifications or an Exos M drive from inheriting X24 data.

Live offers are screened for new single internal 3.5-inch drives and matched to an exact model. SATA and SAS are kept separate. SSDs, external drives, accessories, enclosures, servers, multipacks, MACH.2, Exos Xz host-managed SMR, other drive families and non-new listings are rejected. Warranty source and delivered-label verification remain essential.

Frequently asked questions

Exos generation questions

Is X24 always better than X20?

Not automatically. X24 is newer, but X20 may be a better value if the exact model is new, compatible and properly warranted.

Can I mix X18 and X20 in one RAID?

Sometimes, but matching capacity, sector format, interface and performance is safer. The array will be constrained by its configuration and smallest usable member.

Does a larger cache guarantee faster real-world performance?

No. Workload, queue depth, interface, firmware and array design also matter.

Is Exos M part of this comparison?

This page ends at X24. Exos M is a separate HAMR-CMR generation and is compared directly with X24 on a later sprint page.

Are all listed models SATA?

The representative table uses SATA models. The catalogue also tracks exact SAS variants separately.

Which generation is quietest?

Acoustics vary by exact model and chassis. Enterprise drives should not be chosen from a generation-level noise claim alone.

Primary sources

Cloudzat may earn a commission from qualifying purchases. Product availability, pricing and specifications can change. Confirm the exact Exos model, generation, interface, sector format, security variant, seller, condition and regional warranty route before buying.