# Atomic Racks

> Atomic Racks sells tested enterprise hard drives, SSDs, ECC memory and server parts. Compare specifications, condition notes, and available per-unit test reports. 90-day warranty, up to 2 years on certified tiers.

Agent instructions (shopping, UCP checkout, policies): https://atomicracks.com/agents.md. Every model hub as JSON (specs, units tested, hours, live listings): https://atomicracks.com/models.json. Reliability aggregates: https://atomicracks.com/reliability.json (CC BY 4.0).

## Shop
- [All products](https://atomicracks.com/products)
- [Categories](https://atomicracks.com/categories)
- [Models we test](https://atomicracks.com/models): one page per part number with specs, units tested, pass rate, power-on hours and stock
- [RAM & Memory](https://atomicracks.com/categories/ram-memory): DDR4, DDR5 ECC registered and unbuffered server memory
- [Storage](https://atomicracks.com/categories/storage): Enterprise SSDs, SAS/SATA HDDs, and NVMe drives
- [Networking](https://atomicracks.com/categories/networking): NICs, transceivers, PoE devices, and connectivity gear

## Compare
- [All comparisons](https://atomicracks.com/compare): side-by-side drive comparisons with spec tables and our test data
- [Seagate Exos X16 vs X18: which to buy used](https://atomicracks.com/compare/exos-x16-vs-x18): Seagate Exos X16 vs X18 side by side: capacities, cache, workload, power and part numbers, with our tested units, hours and live stock for each.
- [WD Ultrastar HC530 vs HC550 vs HC570](https://atomicracks.com/compare/hc530-vs-hc550-vs-hc570): WD Ultrastar DC HC530, HC550 and HC570 compared: capacity, platters, recording, transfer and part numbers, with our tested units and live stock.
- [Used enterprise drive vs new NAS drive](https://atomicracks.com/compare/used-enterprise-vs-new-nas): Five-year cost per TB of a used enterprise drive vs a new NAS drive, with dated example prices, power, workload rating, warranty and noise compared.
- [Atomic Racks vs ServerPartDeals vs goHardDrive](https://atomicracks.com/compare/atomic-racks-vs-serverpartdeals-vs-gohardrive): What you get from Atomic Racks, ServerPartDeals and goHardDrive: test reports, hours disclosure, sanitization, warranty and returns, as of November 2026.

## Trust and policies
- [About Atomic Racks](https://atomicracks.com/about)
- [FAQ](https://atomicracks.com/faq)
- [Warranty](https://atomicracks.com/warranty)
- [Returns and RMA](https://atomicracks.com/rma)
- [Sell your hardware](https://atomicracks.com/sell-hardware)
- [Cost per TB calculator](https://atomicracks.com/calculator)
- [How we test](https://atomicracks.com/how-we-test)
- [Usage tiers](https://atomicracks.com/tiers)
- [Data destruction](https://atomicracks.com/data-destruction)
- [Used enterprise drive reliability report (JSON at /reliability.json, CC BY 4.0)](https://atomicracks.com/reliability)
- [Shipping policy](https://atomicracks.com/policies/shipping-policy)
- [Refund policy](https://atomicracks.com/policies/refund-policy)

## Models
- [Seagate Exos X18 18TB SATA (ST18000NM000J)](https://atomicracks.com/models/st18000nm000j): tested 28 units, median hours 25,568
- [Seagate Exos X16 10TB SAS (ST10000NM002G)](https://atomicracks.com/models/st10000nm002g): tested 21 units, median hours 2,356
- [Western Digital Ultrastar DC HC550 18TB SAS (WUH721818AL4200)](https://atomicracks.com/models/wuh721818al4200): tested 19 units, median hours 12,784
- [Western Digital Ultrastar DC HC530 14TB SAS (WUH721414AL5204)](https://atomicracks.com/models/wuh721414al5204): tested 18 units, median hours 25,170
- [Seagate Exos X16 16TB SAS (ST16000NM002G)](https://atomicracks.com/models/st16000nm002g): tested 16 units, median hours 27,178
- [Seagate Exos X16 14TB SATA (ST14000NM001G)](https://atomicracks.com/models/st14000nm001g): tested 10 units, median hours 17,542
- [Seagate BarraCuda 8TB SATA (ST8000DM004)](https://atomicracks.com/models/st8000dm004): tested 7 units, median hours 3,040
- [Seagate Exos 2.4TB SAS (DL2400MM0159)](https://atomicracks.com/models/dl2400mm0159): tested 6 units, median hours 40,748
- [Seagate Exos 12TB SATA (ST12000NM0127)](https://atomicracks.com/models/st12000nm0127): tested 6 units, median hours 52,310
- [Micron 5200 ECO 1.92TB SATA (MTFDDAK1T9TDC)](https://atomicracks.com/models/mtfddak1t9tdc): tested 4 units, median hours 14,380
- [Micron 5300 PRO 1.92TB SATA (MTFDDAK1T9TDS)](https://atomicracks.com/models/mtfddak1t9tds): tested 4 units, median hours 20,628
- [Seagate IronWolf 12TB SATA (ST12000VN0008)](https://atomicracks.com/models/st12000vn0008): tested 4 units, median hours 10,740
- [Western Digital Ultrastar DC HC550 (WUH721818AL5204)](https://atomicracks.com/models/wuh721818al5204): tested 4 units
- [Toshiba AL15SE 2.4TB SAS (AL15SEB24EQY)](https://atomicracks.com/models/al15seb24eqy): tested 3 units, median hours 41,772
- [HGST Ultrastar C10K1800 1.8TB SAS (HUC101818CS4204)](https://atomicracks.com/models/huc101818cs4204): tested 3 units, median hours 21,238
- [HGST Ultrastar He10 10TB SAS (HUH721010AL42C0)](https://atomicracks.com/models/huh721010al42c0): tested 3 units, median hours 40,444
- [Seagate BarraCuda 24TB SATA (ST24000DM001)](https://atomicracks.com/models/st24000dm001): tested 3 units, median hours 5,927
- [Western Digital WD Gold 18TB SATA (WD181KRYZ)](https://atomicracks.com/models/wd181kryz): tested 3 units, median hours 48,415
- [HGST Ultrastar 7K4000 (Sun/Oracle OEM) 4TB SAS (H7240AS60SUN4.0T)](https://atomicracks.com/models/h7240as60sun4-0t): tested 2 units, median hours 19,098
- [Seagate 4TB SAS (ST4000NM0023)](https://atomicracks.com/models/st4000nm0023): tested 2 units, median hours 2,610
- [PNY CS900 1TB SATA (CS900)](https://atomicracks.com/models/cs900): tested 1 unit, median hours 4,474
- [HPE Read Intensive SATA SSD 1.92TB SATA (MK001920GWUGK)](https://atomicracks.com/models/mk001920gwugk): tested 1 unit, median hours 20,673
- [Seagate Exos 7E2 1TB SATA (ST1000NM0008)](https://atomicracks.com/models/st1000nm0008): tested 1 unit, median hours 19,901
- [Seagate Exos X12 12TB SAS (ST12000NM0027)](https://atomicracks.com/models/st12000nm0027): tested 1 unit, median hours 33,802
- [Seagate 16TB SATA (ST16000NE000-2RW103)](https://atomicracks.com/models/st16000ne000-2rw103): tested 1 unit, median hours 188
- [Seagate Exos X18 16TB SATA (ST16000NM000J)](https://atomicracks.com/models/st16000nm000j): tested 1 unit, median hours 35,746

## Guides
- [How to Read a SMART Report Before Buying a Used Hard Drive](https://atomicracks.com/blogs/news/how-to-read-a-smart-report): Five SMART attributes tell you almost everything about a used drive's health. Here's what they mean, what's normal, and what should make you walk away.
- [Are Used Enterprise Drives Safe? What Power-On Hours Really Tell You](https://atomicracks.com/blogs/news/are-used-enterprise-drives-safe): 30,000 hours sounds scary until you understand how enterprise drives are engineered — and where the real risk actually lives.
- [RDIMM vs UDIMM: Why Your Server Won't Boot with the Wrong Memory](https://atomicracks.com/blogs/news/rdimm-vs-udimm-server-memory): Registered, unbuffered, load-reduced — server memory names are cryptic and mixing them is the #1 cause of no-POST tickets. Here's the five-minute version.
- [SAS vs SATA for a Homelab NAS: What Actually Matters](https://atomicracks.com/blogs/news/sas-vs-sata-homelab-nas): SAS drives are often cheaper than SATA on the used market — but can you even use them? A practical compatibility and value guide.
- [The Homelab Buyer's Guide to Used Enterprise SSDs](https://atomicracks.com/blogs/news/used-enterprise-ssd-buyers-guide): A used enterprise SSD at 95% health often outlasts a brand-new consumer drive. Here's the endurance math and the three numbers to check.
- [SFP+, SFP28, and Vendor Coding: Will This Optic Work in My Switch?](https://atomicracks.com/blogs/news/sfp-transceiver-compatibility-guide): Same cage, different rules. A field guide to transceiver form factors, vendor lock, and the DAC-vs-optic decision.
- [How Many Power-On Hours Is Too Many for a Used Hard Drive?](https://atomicracks.com/blogs/news/how-many-power-on-hours-is-too-many): Hours are a proxy for wear, not a verdict. What 40,000 hours means, how it compares to workload rating, and why error history matters more.
- [Reallocated, Pending and Uncorrectable Sectors: What Fails a Drive](https://atomicracks.com/blogs/news/reallocated-pending-uncorrectable-sectors): SMART 5, 197 and 198 explained, raw versus normalized values, SAS grown defects and medium errors, and the thresholds that fail a used drive.
- [Best Used Enterprise Drives for TrueNAS (and How to Choose Them)](https://atomicracks.com/blogs/news/best-used-enterprise-drives-for-truenas): CMR only, HBA in IT mode, matched capacity per vdev, RAIDZ2 widths of six to ten, 4Kn vs 512e and error recovery control, with model picks.
- [Seagate Exos X16 vs X18: Which to Buy Used](https://atomicracks.com/blogs/news/seagate-exos-x16-vs-x18): Same helium 7200 rpm platform and 256 MB cache; the X18 adds 18 TB. Spec table, part-number decoding, SATA vs SAS, and what differs in practice.
- [WD Ultrastar DC HC530 vs HC550 vs HC570](https://atomicracks.com/blogs/news/wd-ultrastar-hc530-vs-hc550-vs-hc570): Three generations of one helium platform at 14, 16 to 18 and 22 TB. Specs, part numbers, 512e vs 4Kn, EAMR and OptiNAND, and which to buy used.
- [Helium Hard Drives: Lifespan, Failure Modes and What to Check Used](https://atomicracks.com/blogs/news/helium-hard-drive-lifespan): Why drives are helium-sealed, what a leak does, SMART attribute 22, what the observational longevity evidence shows, and a used-buyer checklist.
- [Unraid Parity Drive: Size, Speed and Why Used Enterprise Works](https://atomicracks.com/blogs/news/unraid-parity-drive-guide): Parity must be at least as large as the biggest data drive and sets write speed. Sizing ahead, dual parity, enterprise vs NAS drives, and burn-in.
- [DDR4 RDIMM Compatibility for Dell R730/R740 and HPE Gen9/Gen10](https://atomicracks.com/blogs/news/ddr4-rdimm-compatibility-dell-hpe): Speed ceilings by CPU generation, why RDIMM and LRDIMM never mix, ranks and x4 vs x8, down-clocking at three DIMMs per channel, OEM vs generic parts.
- [Using a SAS Drive in a Desktop or NAS: HBAs, Cables and 520-Byte Sector Reformatting](https://atomicracks.com/blogs/news/sas-drive-in-desktop-or-nas): Why SAS will not plug into SATA, which LSI HBA to buy, forward breakout cables, and how to sg_format 520 or 528 byte array drives back to 512 or 4096.
- [Used Enterprise SSD Endurance: Reading TBW, Wear Level and Percentage Used](https://atomicracks.com/blogs/news/enterprise-ssd-endurance-tbw-wear): TBW and DWPD conversion, where the wear number lives on NVMe and SATA drives, how to read smartctl, what 95 percent health means, and why PLP matters.
- [How to Securely Erase a SAS Drive: sg_format and Sanitize](https://atomicracks.com/blogs/news/how-to-securely-erase-a-sas-drive): Seven steps to wipe a SAS hard drive with sg3_utils: identify, record SMART, check sanitize support, pick crypto erase or overwrite, launch, verify, and document against NIST 800-88.
- [Shucked vs Enterprise Drives: Which Is the Better Deal?](https://atomicracks.com/blogs/news/shucked-drives-vs-enterprise-drives): What shucking gets you and what it costs: white-label and desktop drives, the 3.3V pin, lost warranty, SMR risk, workload ratings and burn-in, compared with tested used enterprise drives.
- [10K SAS 2.5-Inch Drives: Still Worth Buying in 2026?](https://atomicracks.com/blogs/news/are-10k-sas-2-5-inch-drives-still-worth-buying): Where 2.5-inch 10K SAS drives still make sense: filling Dell and HPE small form factor bays, VM boot arrays and cheap redundancy, versus 7200 rpm capacity drives and enterprise SSDs.
- [SFP28 25G Transceiver Coding: Cisco, Mellanox, Arista](https://atomicracks.com/blogs/news/sfp28-25g-transceiver-coding-compatibility): Why 25G links fail and how to fix them: vendor EEPROM coding, RS-FEC vs BASE-R vs no FEC, DAC, AOC, SR and LR choices, 100G breakout and checking modules with ethtool -m.
- [Building a 100TB+ Homelab Array on Used Enterprise Drives](https://atomicracks.com/blogs/news/100tb-homelab-array-on-used-enterprise-drives): Layouts, parts, power and cost for a 100 TB home NAS: 8x 16 TB or 10x 14 TB in RAIDZ2, LSI 9300-8i in IT mode, spin-up current, cooling, electricity math and ZFS vs Unraid vs SnapRAID.
- [Buying Matched Drive Lots: Firmware, Batches and RAID](https://atomicracks.com/blogs/news/buying-matched-drive-lots-for-raid): Why matched model, capacity, sector format and firmware matter in RAIDZ, mdadm and Unraid, the case for mixing batches, SAS and SATA on expanders, and how many spares to keep.

## Test reports
Every certified unit has a public test report at https://atomicracks.com/report/unit-<id>. The QR code on the unit's tamper seal opens https://atomicracks.com/r/<id>, which redirects to that report.