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.
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 Enterprise ST3000NM0025 3TB 7200RPM SAS 12.0 GB/s 128MB 512n Enterprise Hard Drive (3.5 inch, Exos 7E8 HDD 512N SAS)
Seagate Exos 7E8 ST4000NM005A 4 TB Hard Drive - Internal - SAS (12Gb/s SAS)
Seagate Exos 7E8 ST4000NM0115 4TB 7.2K RPM SATA 6Gb/s 512e 128MB 3.5inch Hard Drive (Renewed)
Seagate EXOS X20 18TB SAS 3.5IN 7200RPM 6GB/S 512E/4K
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
Seagate ST18000NM003D 18TB Exos X20 SATA Hard Drive, 3.5" HDD, SATA 6Gb/s, 7200rpm, 256MB Cache, 512E, 4.16ms, NCQ
Seagate Exos X24 16TB Enterprise Internal Hard Drive HDD - 6GB/s SAS 7200RPM 2.5M MTBF (ST16000NM002H)
Seagate Technology ST20000NM002H 20TB Exos X24 HDD 3.5 SATA 7200 ISE Bare Hard Drive
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 He12 | HUH721212ALE600 | 12TB 7.2K RPM SATA-6Gb/s 3.5" 256MB cache Hard Disk Drive
HGST 0B36047 - Ultrastar 7K6 HUS726T6TAL5204 - Hard Drive - 6 TB - Internal - 3.5" - SAS 12Gb/s - 7200 RPM - Buffer: 256 MB
Western Digital Ultrastar DC HC550 18 TB Hard Drive - 3.5" Internal - SAS (12Gb/s SAS)
WD-40 Ultrastar HE12 12TB SAS 512E
HGST Ultrastar He12 HUH721212AL4201 12 TB Hard Drive - SAS [12Gb/s SAS] - 3.5 Drive - Internal
WD Ultrastar DC HC570 0F48155 22 TB Hard Drive - 3.5" Internal - SATA (SATA/600) - Conventional Magnetic Recording (CMR) Method
Western Digital WUH721414ALE6L4 14TB Ultrastar DC HC530 SATA HDD - 7200 RPM Class, SATA 6 Gb/s, 512MB Cache, 3.5"
Western Digital WD Ultrastar HC570 WUH722222ALE6L4 22TB 7200RPM 3.5'' Desktop HDD 0F48155
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.
Western Digital Ultrastar DC HC550 18 TB Hard Drive - 3.5" Internal - SAS (12Gb/s SAS)
WD Ultrastar DC HC570 0F48155 22 TB Hard Drive - 3.5" Internal - SATA (SATA/600) - Conventional Magnetic Recording (CMR) Method
Seagate EXOS X20 18TB SAS 3.5IN 7200RPM 6GB/S 512E/4K
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
Western Digital WUH721414ALE6L4 14TB Ultrastar DC HC530 SATA HDD - 7200 RPM Class, SATA 6 Gb/s, 512MB Cache, 3.5"
Seagate ST18000NM003D 18TB Exos X20 SATA Hard Drive, 3.5" HDD, SATA 6Gb/s, 7200rpm, 256MB Cache, 512E, 4.16ms, NCQ
Seagate Exos X24 16TB Enterprise Internal Hard Drive HDD - 6GB/s SAS 7200RPM 2.5M MTBF (ST16000NM002H)
Seagate Technology ST20000NM002H 20TB Exos X24 HDD 3.5 SATA 7200 ISE Bare Hard Drive
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)
Seagate-IMSourcing Exos X16 ST12000NM003G 12 TB Hard Drive - Internal - SATA [SATA/600]
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)
Seagate 14TB HDD Exos X14 7200 RPM 512e/4Kn SATA 6Gb/s 256MB Cache 3.5-Inch Enterprise Hard Drive (ST14000NM0018)
Seagate Exos X14 ST10000NM0528 10 TB Hard Drive - 3.5" Internal - SAS (12Gb/s SAS)
Western Digital 12TB Ultrastar DC HC520 SATA HDD - 7200 RPM Class, SATA 6 Gb/s, 256MB Cache, 3.5" - HUH721212ALE604 (Renewed)
Western Digital WD Ultrastar dc hc320 hus728t8tl5204 - HDD - 8 TB - SAS 12gb/s 0b36400
Western Digital 14TB Ultrastar DC HC530 SATA HDD - 7200 RPM, SATA 6 Gb/s, 512MB Cache, 3.5" - WUH721414ALE604 (Renewed)
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