18TB SAS 3.5in — Enterprise HDD Signals

3 models — Seagate, Toshiba, WD. OEM premium, spread, and liquidity from secondary market observations.

Data as of 2026-04-15

▶What do these badges mean?
High liquidity50+ observed listings in the last 30 days. Strong price signal.
Medium liquidity10–49 listings. Reasonable basis for benchmarking.
Directional onlyFewer than 5 listings. Treat as directional only — not a pricing benchmark.
Low liquidity5–9 listings. Price signal is weaker — use directionally.
EmergingNewly tracked class. Data still accumulating.
Coming soonPlanned for coverage. No pricing data yet.
SeagateExos X18
Seagate Exos X18 18TB SAS
Coming soon→
ToshibaMG09
Toshiba MG09 18TB SAS
Spread 19%4 obs· last seen 3d ago
Directional signal only — fewer than 5 observations
Directional only→
WDUltrastar DC HC550
WD Ultrastar DC HC550 18TB SAS
Coming soon→

Other SAS 3.5in capacities

6TB →8TB →14TB →16TB →20TB →22TB →

Related categories

Server Memory →Server CPUs →
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What's the spread on DDR4 32GB RDIMM right now?
For DDR4 32GB RDIMM, OEM parts are clearing 18–22% above compatible alternatives. 6 active sellers, moderate liquidity. Compatible pricing has been stable for 30 days.
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Signals point to a stable-to-softening trend for compatible. If your timeline allows 2–4 weeks, holding may improve your position. OEM premiums are holding firm — only worth it if your platform requires validated memory.
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