GPUs
Visual inspection, output and port test, sustained 3D stress loop, artifact check, fan behavior, thermals, and stability percentage.
How we test & warranty
The listing is only as good as the evidence behind it.
Our grade describes cosmetic condition. Our bench record describes function. We publish both, because one should never be used to hide the other.
TierConcrete standardCoverage
New partsFactory-new or sealed/open-box as explicitly listed. Coastline verifies receipt and DOA status.Manufacturer pass-through + 30-day Coastline DOA
Certified Used · Grade AFully functional. Minimal cosmetic wear. Complete major accessories unless stated.90-day Coastline warranty
Certified Used · Grade BFully functional. Visible normal wear photographed in the listing. Accessories inventoried.60-day Coastline warranty
Certified Used · Grade CFully functional value tier. Clear cosmetic wear or missing nonessential accessories, all disclosed.30-day Coastline warranty
Full build laborAssembly, cabling, cooling installation, BIOS baseline, and workmanship.1-year Coastline labor warranty
AI software setupAgreed Linux, driver, runtime, model-interface, and workflow configuration.14 days free follow-up support
Methodology
Tests match the category.
CPUs & memory
Socket/contact inspection, memory training, MemTest86, CPU load loop, clock behavior, and package thermals.
Storage
SMART record, health and writes, surface scan, sustained read/write sample, and thermal observation.
Complete systems
Component-level checks plus CPU/GPU combined load, sleep/wake, networking, front I/O, acoustics, and final burn-in.
We do not list a used item when:
- Artifacts, intermittent errors, or unstable power behavior cannot be resolved.
- Identification, serial information, or provenance is materially inconsistent.
- Damage makes safe shipping or normal use uncertain.
- We cannot reproduce a reliable pass under the category test.