6 Best Alternatives to the Seagate Exos X20 20TB SAS (2026)

How each alternative compares

Seagate Exos 26TB CMR Hard Drive

The Seagate Exos 26TB offers 6TB more capacity than the original 20TB drive, making it ideal for users prioritizing maximum storage density. It uses SATA instead of SAS, which means you lose dual-port redundancy and high-availability path support. This drive provides a 512MB cache, double the original’s 256MB, potentially improving buffer performance for large sequential transfers. It retains the 7200 RPM speed and CMR recording technology, ensuring consistent write speeds without the latency issues of SMR. You should choose this if you need more space and do not require the enterprise-grade SAS interface for redundant controller connections. It is a straightforward upgrade in capacity and cache, trading interface complexity for raw volume.

Seagate Exos X22 20TB Renewed HDD

The Seagate Exos X22 matches the original’s 20TB capacity and 7200 RPM speed but switches to a SATA interface. This change removes the dual-port SAS connectivity required for high-availability enterprise arrays, limiting its use to standard SATA controllers. It is offered as renewed hardware, which may affect warranty terms compared to the new original drive. The drive maintains the 3.5-inch form factor and CMR recording technology, ensuring similar performance characteristics for sequential workloads. You might pick this option if you want the same storage volume and rotational speed but prefer SATA compatibility or are seeking a more budget-friendly renewed unit. It sacrifices enterprise redundancy features for broader compatibility and potential cost savings.

Western Digital WD Gold 18TB 7200 RPM Hard Drive

The Western Digital WD Gold 18TB has 2TB less capacity than the original 20TB drive but features a larger 512MB cache. This cache size is double that of the Seagate Exos X20, which can help manage data flow more efficiently during bursty workloads. It uses SATA instead of SAS, so you give up dual-port redundancy and high-availability path support. The drive retains the 7200 RPM speed and 3.5-inch form factor, keeping rotational performance similar. You should consider this if you value larger cache memory and SATA connectivity over maximum capacity and SAS redundancy. It suits users who prioritize buffer performance and standard interface compatibility for their storage needs.

Seagate IronWolf 18TB CMR NAS HDD

The Seagate IronWolf 18TB offers 2TB less capacity than the original but is designed specifically for NAS enclosures. It uses SATA instead of SAS, removing dual-port redundancy and enterprise high-availability features. The drive includes Vibration Reduction Technology and Health Monitoring, features not specified for the Exos X20, making it better suited for multi-bay NAS systems where vibration management is critical. It shares the 7200 RPM speed, CMR technology, and 256MB cache with the original. You should pick this if you are building a NAS rather than an enterprise server and need specialized vibration control. It trades enterprise SAS features for NAS-specific reliability and monitoring tools.

Western Digital 22TB WD Red Pro

The Western Digital WD Red Pro 22TB provides 2TB more capacity than the original 20TB drive. It features a 512MB cache, double the original’s 256MB, which can improve performance for mixed workloads. Like the IronWolf, it uses SATA instead of SAS, so you lose dual-port redundancy and high-availability path support. It maintains the 7200 RPM speed and CMR recording technology, ensuring consistent performance. The drive is designed for high-capacity multi-bay NAS setups, offering robust features for professional users. You should choose this if you need more storage and a larger cache but do not require the SAS interface. It is a strong option for NAS users who prioritize capacity and buffer size over enterprise redundancy.

Western Digital Ultrastar 20TB SAS Hard Drive

The Western Digital Ultrastar 20TB SAS matches the original’s 20TB capacity and 7200 RPM speed, offering a direct competitor in the enterprise segment. It also uses the SAS interface, retaining the potential for dual-port redundancy and high-availability configurations. The drive shares the 3.5-inch form factor, making it physically compatible with the same enclosures. While specific cache size and workload ratings are not detailed in the provided data, it is positioned as an enterprise-grade solution for servers requiring large storage and high throughput. You should consider this if you want an alternative SAS drive with identical capacity and rotational speed. It is suitable for users who prefer Western Digital’s enterprise ecosystem over Seagate’s.

Quick picks

Our 7 picks

1 Best overall

Seagate Exos X20 20TB SAS Hard Drive

Best for: enterprise servers requiring SAS redundancy

Storage Capacity

20TB

Form Factor

3.5-Inch

Hardware Interface

SAS 12Gb/s

Rotational Speed

7200 RPM

Cache Size

256MB

Recording Technology

CMR

View on Amazon: Seagate Exos X20 20TB SAS Hard Drive Affiliate link

This is a 20TB enterprise hard drive with SAS 12Gb/s connectivity and 7200 RPM rotational speed. It uses helium-sealed CMR technology for stable performance and includes 256MB of cache. The drive supports dual-port connections for high availability in RAID arrays. It is rated for 550TB per year of workload and features self-encrypting drive security. You should use this drive in servers or NAS systems that require SAS controllers, not in standard desktop PCs.

Pros

• 20TB storage capacity for large data sets
• SAS 12Gb/s interface with dual-port support
• 7200 RPM rotational speed for fast access
• Helium-sealed design reduces power consumption
• 550TB/year workload rate limit for reliability

Cons

• Requires SAS HBA or RAID controller
• Not compatible with standard desktop PCs
• No SATA interface option available

Good fit if

• You need high-capacity storage for enterprise servers
• You require dual-port SAS for redundancy
• You run RAID arrays with SAS controllers

Skip if

• You connect drives directly to a desktop PC
• Your system only supports SATA interfaces
• You do not have a SAS HBA or RAID controller

Verdict: Seagate Exos X20 20TB SAS Enterprise Drive offers high-capacity storage with dual-port SAS connectivity for enterprise environments. It fits users who need redundant storage paths and high workload ratings for mission-critical data.

2 Also great

Seagate Exos 26TB CMR Hard Drive

Best for: High-capacity enterprise storage needs

Storage Capacity

26TB

Form Factor

3.5 in

Hardware Interface

SATA 6Gb/s

Rotational Speed

7200 RPM

Cache Size

512MB

Recording Technology

CMR

View on Amazon: Seagate Exos 26TB CMR Hard Drive Affiliate link

This Seagate Exos drive offers 26TB of storage using CMR technology and a 7200 RPM rotational speed. It features a 512MB cache and a SATA 6Gb/s interface for reliable data transfer. The enterprise-class build supports continuous operation with a high workload rating. You get more capacity than the standard 20TB models in this guide, making it ideal for users needing maximum space in a 3.5-inch form factor.

Pros

• 26TB storage capacity exceeds the 20TB baseline
• 512MB cache for improved performance
• 7200 RPM rotational speed for sustained workloads
• CMR recording technology for reliability

Cons

• SATA interface is slower than the SAS option
• Higher power consumption due to 7200 RPM
• Larger physical size may not fit small enclosures

Good fit if

• You need more than 20TB of storage
• You want enterprise-class reliability
• You prefer CMR technology

Skip if

• You require SAS connectivity
• You need a lower power drive
• You are on a tight budget

Verdict: Seagate Exos 26TB 7200 RPM SATA is the best choice if you need maximum capacity and do not require SAS interfaces.

3 Also great

Seagate Exos X22 20TB Renewed HDD

Best for: High-capacity SATA storage needs

Storage Capacity

20TB

Form Factor

3.5-inch

Hardware Interface

SATA 6Gb/s

Rotational Speed

7200RPM

Weight

1.83 pounds

View on Amazon: Seagate Exos X22 20TB Renewed HDD Affiliate link

This renewed Seagate Exos X22 offers 20TB of storage on a 3.5-inch drive. It spins at 7200 RPM and connects via SATA 6Gb/s. The helium-sealed design supports large data transfers. You get a 2-year reseller warranty. It fits users who need high capacity and enterprise reliability without the cost of SAS interfaces.

Pros

• 20TB storage capacity
• 7200 RPM rotational speed
• SATA 6Gb/s interface
• Helium side-sealing technology

Cons

• Renewed condition
• SATA interface instead of SAS
• 2-year reseller warranty only

Good fit if

• You need maximum storage density
• You prefer SATA compatibility
• You want enterprise-grade reliability

Skip if

• You require SAS connectivity
• You need a new unit warranty
• You prefer lower power consumption

Verdict: Seagate Exos X22 20TB SATA is a high-capacity drive for users who value storage density over interface type. It suits those who can accept renewed hardware for better value.

4 Best budget

Western Digital WD Gold 18TB 7200 RPM Hard Drive

Best for: SATA users needing high RPM performance

Storage Capacity

18TB

Form Factor

3.5"

Hardware Interface

SATA 6 Gb/s

Rotational Speed

7200 RPM Class

Cache Size

512 MB

Recording Technology

EAMR

View on Amazon: Western Digital WD Gold 18TB 7200 RPM Hard Drive Affiliate link

This Western Digital drive offers 18TB of storage in a 3.5-inch form factor. It uses SATA 6 Gb/s interfaces and runs at 7200 RPM. The 512 MB cache helps manage data flow. It supports workloads up to 550TB per year. HelioSeal technology reduces power draw. You get vibration protection for stability. This model suits users needing high performance.

Pros

• 18TB storage capacity
• 7200 RPM rotational speed
• 512 MB cache size
• 550TB annual workload limit
• Vibration protection technology

Cons

• 18TB is smaller than the 20TB standard on this list
• SATA interface is slower than the SAS options listed
• No SED encryption mentioned in specifications

Good fit if

• You need high rotational speed for performance
• You prefer SATA connectivity over SAS
• You want enterprise-grade workload reliability

Skip if

• You require the maximum 20TB capacity
• You need SAS interface compatibility
• You require hardware encryption features

Verdict: WD Gold 18TB Enterprise HDD delivers strong performance with its 7200 RPM speed and 512 MB cache. It fits users who prioritize SATA connectivity and high workload limits over maximum capacity.

5 Best 256mb cache

Seagate IronWolf 18TB CMR NAS HDD

Best for: 8-bay NAS enclosures needing CMR reliability

Storage Capacity

18TB

Form Factor

3.5 Inch

Hardware Interface

SATA 6Gb/s

Rotational Speed

7200 RPM

Cache Size

256MB

Recording Technology

CMR

View on Amazon: Seagate IronWolf 18TB CMR NAS HDD Affiliate link

The Seagate IronWolf 18TB is a 3.5-inch SATA 6Gb/s drive designed for NAS enclosures up to 8-bay. It uses CMR recording technology and spins at 7200 RPM. The drive includes 256MB of cache. It targets multi-user environments with vibration reduction and health monitoring. You should choose this if you need reliable NAS storage with a balance of speed and capacity.

Pros

• CMR recording technology for consistent performance
• 256MB cache size for faster data access
• Optimized for up to 8-bay NAS systems
• 7200 RPM rotational speed

Cons

• 18TB capacity is smaller than the 20TB Exos X20
• SATA interface is slower than the SAS 12Gb/s connection
• Heavier at 1.52 pounds compared to some alternatives

Good fit if

• You need a drive for an 8-bay NAS enclosure
• You prefer CMR technology over SMR
• You want a balance of capacity and speed

Skip if

• You require the maximum 20TB capacity
• You need SAS connectivity for enterprise servers
• You prioritize the largest possible storage density

Verdict: Seagate IronWolf 18TB NAS HDD offers solid NAS-specific features like CMR and 256MB cache. It fits users who value vibration reduction and health monitoring over raw capacity.

6 Also great

Western Digital 22TB WD Red Pro

Best for: high-capacity multi-bay NAS setups

Storage Capacity

22TB

Form Factor

3.5-inch

Hardware Interface

SATA 6 Gb/s

Rotational Speed

7200 RPM

Cache Size

512 MB

Recording Technology

CMR

View on Amazon: Western Digital 22TB WD Red Pro Affiliate link

The WD Red Pro 22TB is a 3.5-inch internal hard drive built for RAID-optimized NAS systems. It features CMR recording, a 7200 RPM rotational speed, and a 512 MB cache. This drive is designed for high-intensity 24x7 multi-user environments and supports a workload rate of 550TB per year. You get extensive compatibility testing with major NAS vendors. It offers higher capacity and cache than many alternatives.

Pros

• 22TB storage capacity exceeds the 20TB baseline of the list
• 7200 RPM rotational speed for consistent performance
• 512 MB cache size supports heavy data throughput
• CMR recording technology ensures reliable write speeds
• Rated for 550TB/yr annualized workload rate

Cons

• SATA interface is slower than the SAS 12Gb/s option
• Heavier build at 1.48 pounds compared to lighter drives
• Higher power consumption typical of 7200 RPM enterprise-class drives

Good fit if

• You need more than 20TB of storage in a single bay
• You run a high-intensity 24x7 multi-user NAS environment
• You prioritize cache size and rotational speed for performance

Skip if

• You require the faster SAS 12Gb/s interface
• You are building a low-power or quiet home NAS
• You prefer the lower cost of 18TB or 20TB options

Verdict: WD Red Pro 22TB 7200 RPM NAS Drive is a high-capacity option for users who need more space than the standard 20TB drives offer. It suits professionals running heavy workloads who value the larger 512 MB cache and 7200 RPM speed over the SAS interface found in the top pick.

7 Best premium

Western Digital Ultrastar 20TB SAS Hard Drive

Best for: Enterprise servers needing 20TB SAS storage

Storage Capacity

20 TB

Form Factor

3.5"

Hardware Interface

SAS 12Gb/s

Rotational Speed

7200 RPM

Cache Size

512 MB

View on Amazon: Western Digital Ultrastar 20TB SAS Hard Drive Affiliate link

The WD Ultrastar DC HC560 is a 20 TB internal hard drive designed for enterprise storage. It uses a 3.5-inch form factor and rotates at 7200 RPM. The drive connects via SAS 12Gb/s interface. It includes 512 MB of cache buffer. This model suits users needing high capacity and fast data transfer rates for server environments.

Pros

• 20 TB storage capacity
• 7200 RPM rotational speed
• 512 MB cache buffer
• SAS 12Gb/s interface

Cons

• SAS interface limits compatibility to supported servers
• 3.5-inch form factor requires large drive bays

Good fit if

• You need 20 TB of storage capacity
• You require a 7200 RPM drive for performance
• Your system supports SAS 12Gb/s connections

Skip if

• You need a SATA interface for standard desktops
• You require a 2.5-inch drive for compact systems
• You prefer lower rotational speeds for quiet operation

Verdict: WD Ultrastar DC HC560 20TB SAS delivers enterprise-grade speed and capacity for servers that support SAS connections. It is ideal for users prioritizing high throughput and large storage in a 3.5-inch form factor.

Specifications side by side

Frequently asked questions

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