CenturyLink (rebranding as Quantum Fiber) operates pure fiber optic and DSL broadband networks across 36 US states. Offering 200 Mbps, 940 Mbps (1 Gig), and up to 8 Gig fiber plans with zero contracts and zero data caps, Quantum Fiber is a premier choice for remote work and low-ping gaming. We benchmark CenturyLink speeds.
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Quantum Fiber: CenturyLink's Fiber Rebrand
Quantum Fiber is CenturyLink's fiber-optic product line, distinct from the company's older copper DSL service that still serves parts of its 36-state legacy footprint. As with Windstream, confirming whether a specific address has true Quantum Fiber or legacy DSL matters more than the parent brand name when evaluating realistic speed.
No-Contract, No Data Cap
Quantum Fiber's no-contract, uncapped structure matches the pattern seen across fiber ISPs throughout this guide series — a direct consequence of fiber's dedicated-line architecture not needing the congestion-management tools cable ISPs historically adopted data caps to justify.
Speed Tiers and What They Actually Deliver
Quantum Fiber's tiers span from roughly 200 Mbps up through 8 Gig in the most built-out markets — the top-end multi-gigabit tiers, as with Google Fiber and AT&T's equivalent tiers, mainly benefit wired connections to a server or workstation rather than typical WiFi-connected household devices, which rarely need or can even fully use that much bandwidth.
Confirming Fiber vs DSL at Your Address
CenturyLink/Quantum's online availability checker distinguishes between fiber and DSL service at a specific address — checking this directly avoids comparing DSL-level real-world speeds against fiber-tier marketing claims that don't apply to your specific service type.