Western Digital Ultrastar 18TB Enterprise HDD (Clean IDC Pull)

The WD 18TB occupies a straightforward position in MillionMiner's catalog: highest capacity per dollar for bulk storage alongside GPU compute hardware. At $350 for 18TB ($19.44 per TB), it undercuts the Seagate 16TB at $450 ($28.13 per TB) by 31 percent on a cost-per-terabyte basis while delivering 12.5 percent more raw capacity. For operators buying storage alongside RTX 5090 systems, A100 servers, or multi-GPU mining rigs, the WD 18TB is the default storage recommendation unless a specific Seagate requirement exists.The Ultrastar DC HC550 18TB is WD's data center workhorse for hyperscale and cloud environments. 9-disk helium sealed platform (6th generation HelioSeal) with EAMR… (Energy-Assisted Magnetic Recording) improving writability and areal density, and Triple Stage Actuator (TSA) enhancing head-positioning accuracy for better performance and reliability. 7,200 RPM sustained with 512MB cache, significantly larger than the Seagate Exos X16's 256MB cache. The larger cache benefits sequential read/write workloads (dataset loading, model weight retrieval, backup operations) with better burst performance.CMR recording throughout the Ultrastar lineup. CMR writes data to non-overlapping tracks, providing consistent write performance regardless of workload pattern. SMR drives overlap tracks and require internal data reorganization during random writes, causing unpredictable latency spikes. For AI training pipelines that shuffle and write datasets repeatedly, for database backends serving inference results, and for any workload with mixed read/write patterns, CMR is the correct recording technology. Every Ultrastar data center HDD uses CMR.Enterprise reliability specifications: 2.5 million hour MTBF, 550TB per year sustained workload rate (read plus write), 5-year limited warranty when new, 0.35 percent annualized failure rate. Rotational vibration safeguard sensors for multi-drive enclosures where adjacent drive vibration can degrade accuracy. These specifications apply to the drive when new; IDC pull drives carry accumulated wear against these baselines."Clean IDC Pull" condition: same caveats as the Seagate 16TB listing. Used enterprise hardware from decommissioned data centers. Controlled environment operation history. Tested and data-wiped. Verify before deploying: exact model number and firmware, interface (SATA 6Gb/s or SAS 12Gb/s), total power-on hours (under 20,000 excellent, under 30,000 good), reallocated sector count (zero is target), current pending sectors (zero), SMART overall status (PASS).The buy/sell spread: MillionMiner buys at $310 and sells at $350. This means MillionMiner is also a buyer of data center pull inventory from operators decommissioning storage. The two-way market creates procurement flexibility: buy drives when building systems, sell drives when upgrading or decommissioning.Capacity context for GPU compute deployments. A single 18TB drive stores: approximately 1,280 copies of a 14GB Llama 3 8B model at FP16, the complete ImageNet dataset (150GB) 120 times, a Bitcoin full node (600GB) with 17TB remaining for additional data, or multiple TB-scale AI training datasets with room for model checkpoints and logs. 18TB in a single bay reduces drive count, power, cabling, and failure points versus multiple smaller drives.