Seagate Exos vs WD Ultrastar
Exos and Ultrastar are the two dominant enterprise HDD families for datacenter, homelab, and high-capacity server storage. Both are rated for 24/7 operation, carry 5-year warranties at retail, and are designed for multi-drive chassis with vibration tolerance. In practice the choice often comes down to price at the capacity you need, firmware compatibility with your HBA or backplane, and whether you prefer Seagate or WD support.
Quick comparison
Exos (Seagate) and Ultrastar (WD/HGST legacy) both target the same workloads: always-on servers, JBODs, and storage arrays. Exos X-series tops out at 24 TB with helium-sealed models; Ultrastar HC-series reaches similar capacities. Both offer SAS and SATA interfaces. Workload ratings are typically 550 TB/year, with 2.5M-hour MTBF. For most buyers, the lowest price per TB at your target capacity is the right pick.
Prices updated daily from Amazon.com. All links go directly to the retailer. Details.
Bottom line: the lowest price-per-TB pick on this page right now is the Seagate Exos x10 10TB SATA 6Gb/s 256MB Cache Enterprise Hard Drive 3.5" (ST10000NM0086), 10 TB used, at $239.00 ($23.90/TB) on Amazon.com. Check the current price.
Seagate Exos, Current Prices
New Seagate Exos enterprise drives sorted by price per terabyte. Includes Exos X-series helium models across all available capacities.
Seagate ST10000NM0146 10TB Exos X10 HDD SATA 3.5 7200 256MB External Hard Drives
Seagate EXOS X20 18TB SAS 3.5IN 7200RPM 6GB/S 512E/4K
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
ST14000NM0048 Seagate 14TB SAS 12 Gb/s (Not SATA) Exos X14 (New with Warranty) 3.5 Inch 7200 RPM 256MB Cache 512e 4Kn Enterprise Hard Drive HDD
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Seagate-IMSourcing Exos X16 ST12000NM003G 12 TB Hard Drive - Internal - SATA [SATA/600]
Seagate Exos X24 16TB Enterprise Internal Hard Drive HDD - 6GB/s SAS 7200RPM 2.5M MTBF (ST16000NM002H)
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Seagate ST18000NM003D 18TB Exos X20 SATA Hard Drive, 3.5" HDD, SATA 6Gb/s, 7200rpm, 256MB Cache, 512E, 4.16ms, NCQ
Seagate Enterprise ST6000NM0125 6TB 7200RPM SATA 6.0 GB/s 256MB 4Kn Enterprise Hard Drive (3.5 inch, Exos 7E8 HDD 4KN SATA)
Seagate 14TB HDD Exos X14 7200 RPM 512e/4Kn SATA 6Gb/s 256MB Cache 3.5-Inch Enterprise Hard Drive (ST14000NM0018)
WD Ultrastar, Current Prices
New Western Digital Ultrastar enterprise drives sorted by price per terabyte. The Ultrastar HC-series carries on the HGST legacy of reliability.
HGST Ultrastar 7K6000 HUS726060ALE610 0F23001 6TB 7200 RPM SATA 3.5" 512E ISE 128MB Cache Enterprise Hard Drive
Hitachi HGST Ultrastar He10 | HUH721010ALN600 | 0F27502 | 10TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5" 4Kn Helium Platform Enterprise Hard Drive Bare Drive
Western Digital WUH721414ALE6L4 14TB Ultrastar DC HC530 SATA HDD - 7200 RPM Class, SATA 6 Gb/s, 512MB Cache, 3.5"
Western Digital Ultrastar DC HC550 16 TB Hard Drive - 3.5 Internal - SAS [12Gb/s SAS]
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
HGST Ultrastar He12 HUH721212AL4201 12 TB Hard Drive - SAS [12Gb/s SAS] - 3.5 Drive - Internal
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Western Digital Ultrastar DC HC550 14 TB Hard Drive - 3.5" Internal - SATA (SATA/600) - Conventional Magnetic Recording (CMR) Method - 7200rpm - 550 TB TBW - 512e Format - 5 Year Warranty
HGST Ultrastar He12 HUH721212ALE600 12 TB Hard Drive - 3.5" Internal - SATA (SATA/600) - 7200rpm
Western Digital Ultrastar DC HC550 WUH721816ALE6L4 0F38462 16TB 7.2K RPM SATA 6Gb/s 512e 512MB 3.5" SE HDD
High-Capacity Enterprise (14 TB+)
The largest enterprise drives from both families. More terabytes per slot means fewer bays, fewer HBAs, and lower power per usable TB.
Seagate EXOS X20 18TB SAS 3.5IN 7200RPM 6GB/S 512E/4K
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
ST14000NM0048 Seagate 14TB SAS 12 Gb/s (Not SATA) Exos X14 (New with Warranty) 3.5 Inch 7200 RPM 256MB Cache 512e 4Kn Enterprise Hard Drive HDD
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Western Digital WUH721414ALE6L4 14TB Ultrastar DC HC530 SATA HDD - 7200 RPM Class, SATA 6 Gb/s, 512MB Cache, 3.5"
Seagate Exos X24 16TB Enterprise Internal Hard Drive HDD - 6GB/s SAS 7200RPM 2.5M MTBF (ST16000NM002H)
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Seagate ST18000NM003D 18TB Exos X20 SATA Hard Drive, 3.5" HDD, SATA 6Gb/s, 7200rpm, 256MB Cache, 512E, 4.16ms, NCQ
Western Digital Ultrastar DC HC550 16 TB Hard Drive - 3.5 Internal - SAS [12Gb/s SAS]
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Seagate 14TB HDD Exos X14 7200 RPM 512e/4Kn SATA 6Gb/s 256MB Cache 3.5-Inch Enterprise Hard Drive (ST14000NM0018)
Seagate Exos X18 ST18000NM005J 18 TB Hard Drive - Internal - SAS (12Gb/s SAS) - 7200rpm - 5 Year Warranty
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Refurbished Exos & Ultrastar
Recertified datacenter pulls from both brands. Enterprise drives are designed for 2M+ hour MTBF, so a drive with 20-40K hours of use still has substantial life, ideal for homelabs and non-critical storage.
Why this matters: Refurbished enterprise drives often deliver the lowest price per TB available. Look for sellers that include SMART reports or a seller warranty. Drives with low reallocated sector counts and under 40,000 power-on hours are typically good candidates.
Seagate Enterprise ST3000NM0025 3TB 7200RPM SAS 12.0 GB/s 128MB 512n Enterprise Hard Drive (3.5 inch, Exos 7E8 HDD 512N SAS)
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Seagate Exos x10 10TB SATA 6Gb/s 256MB Cache Enterprise Hard Drive 3.5" (ST10000NM0086)
Seagate Exos X14 ST14000NM0408 14TB 7.2K RPM CMR SATA 6Gb/s 512e 3.5in Hard Drive (Renewed)
Seagate/IBM Exos X16 16TB Enterprise Hard Drive HDD SAS 12Gb/s 256MB Cache 7200 RPM 4Kn CMR Helium Sealed 3.5in Hard Drive ST16000NM002G (Renewed)
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Seagate Exos x12 12TB SATA 6Gb/s 256MB Cache Enterprise Hard Drive 3.5in (ST12000NM0127) (Renewed)
Seagate Exos 7E8 6TB 7200 RPM 512e SAS 12Gb/s 256MB Cache 3.5-Inch Enterprise Hard Drive - ST6000NM0095 (Renewed)
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Seagate Exos X14 ST12000NM0008 12 TB Hard Drive - 3.5" Internal - SATA (SATA/600)
Western Digital HGST Ultrastar He10 HUH721008AL5204 8 TB Hard Drive - 3.5" Internal - SAS (12Gb/s SAS) - 7200rpm - 256 MB Buffer - 5 Year Warranty
SAS interface. Needs a host bus adapter, it will not plug into a normal motherboard.
Frequently Asked Questions
Seagate Exos or WD Ultrastar — which is better?
Both are excellent enterprise lines with near-identical specs: 24/7 operation, ~550 TB/year workloads, 2.5M-hour MTBF, and 5-year retail warranties. Reliability differences are negligible for almost every buyer, so the right pick is simply whichever is cheaper per terabyte at your target capacity. Check both columns on this page on the day you buy.
Do Exos and Ultrastar work in a home NAS?
Yes. Both are overbuilt for home NAS duty and extremely reliable in multi-bay enclosures thanks to their vibration tolerance. The main trade-offs are noise (7200 RPM, no idle spin-down) and power draw. If noise is not a concern, they are among the best value-per-terabyte NAS drives, especially refurbished.
What is the difference between the SATA and SAS versions?
Both lines ship in SATA and SAS. SATA drives plug into any normal motherboard or NAS. SAS drives need a host bus adapter (HBA) and are meant for servers and JBODs — they are often cheaper per terabyte but useless without the controller. Unless you already run an HBA, buy the SATA version.
Are refurbished Exos and Ultrastar drives worth it?
Often yes. Datacenter pulls of both lines are frequently far cheaper per terabyte than new and, rated for 2M+ hours MTBF, usually have substantial life left. The trade-off is a shorter seller warranty and unknown history. Buy from a seller that shows SMART data and offers a return policy, run them redundantly, and keep backups. See our refurbished page for the current used $/TB.
What capacities do Exos and Ultrastar reach?
Both families run from a few terabytes up to 24 TB, with helium-sealed construction from roughly 14 TB and above. At the top capacities the two are closely matched on specs, so again the deciding factor is the live price per terabyte at the size you need.
Related Guides and Articles
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Compare enterprise HDD prices for Seagate Exos and WD Ultrastar. Datacenter-grade drives sorted by price per TB for servers and storage arrays.
Buying guideBest Refurbished Hard Drives
Find the best refurbished and used hard drive deals sorted by price per TB. Enterprise pulls, recertified NAS drives, and high-capacity bargains from Amazon.com.
Buying guideBest HDD Deals Right Now
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