Which switch delivers more PoE power, and how is that power sourced?

The USW-FLEX is specified at 60W total PoE++ (802.3bt) output across its downstream ports, with a single-port maximum output voltage of 54V at 1.11A. It is powered by an upstream PoE++ input (50–57V, listed as 46W or 20W input modes), meaning it requires no local AC adapter and can be daisy-chained from an upstream PoE++ injector or switch — a key advantage for pole-top, junction-box, or conduit-fed installs where running AC is impractical. Power consumption excluding PoE output is listed at 5W.

The USW-FLEX-3 delivers PoE on all five ports and shares the same output voltage spec of 54V at 1.11A. However, its specs indicate it requires external AC power input rather than upstream PoE passthrough. Its _Poe Power field lists PoE++ (802.3bt), while the datasheet summary describes 'Universal PoE (802.3af/at)' — an internal inconsistency in the provided specs. Total PoE budget for the USW-FLEX-3 is not stated in the provided specifications. Buyers requiring a confirmed aggregate watt budget should verify with Ubiquiti's published datasheet before specifying.

For installations where power runs only as PoE from an upstream device — outdoor cabinets, pole mounts, remote IDF closets — the USW-FLEX's documented PoE-in/PoE-out architecture is a concrete, spec-confirmed advantage. The USW-FLEX-3's AC requirement adds an installation dependency that the USW-FLEX avoids.

Which switch is rated for harsher environmental conditions?

The USW-FLEX carries an operating temperature range of -40°C to 55°C (-40°F to 131°F) at 46W PoE output, making it one of the wider-range rated compact switches in the UniFi line. This rating is explicitly tied to the 46W PoE output mode; the spec does not state the range at full 60W output. ESD protection is ±16kV air and ±16kV contact. Storage temperature is -30°C to 70°C.

The USW-FLEX-3 is rated -20°C to 60°C (-4°F to 140°F) for operation, a narrower cold-side floor (20°C warmer at the low end) but a slightly higher upper ceiling (60°C vs 55°C). It shares identical ESD protection (±16kV air, ±16kV contact) and the same storage range (-30°C to 70°C). Country of origin is listed as CN; no equivalent field is provided for the USW-FLEX.

For installations in unheated outdoor enclosures, northern-climate deployments, or cold-storage facilities where ambient temperatures can drop well below -20°C, the USW-FLEX's -40°C lower bound is a meaningful spec advantage. The USW-FLEX-3's higher upper ceiling (60°C vs 55°C) may matter in hot enclosed equipment boxes in direct sun, though neither unit carries an ingress-protection (IP) rating in the provided specs — confirming neither is rated for direct weather exposure without an enclosure.

How do the two switches compare on switching capacity, throughput, and management interface?

The USW-FLEX provides documented switching capacity of 10 Gbps, non-blocking throughput of 5 Gbps, and a forwarding rate of 7 Mpps. VLAN support is explicitly listed at 1,000 VLANs. Management is described as Ethernet-based within the UniFi ecosystem. These figures give integrators concrete numbers for network planning in high-density camera or AP deployments.

The USW-FLEX-3 specifies management via Web GUI and CLI with UniFi integration, and its port speeds are confirmed as 10/100/1000 Mbps on all five ports. However, switching capacity, non-blocking throughput (Gbps), forwarding rate (Mpps), and VLAN count are not stated in the provided specifications. The management interface description is more detailed — explicitly naming Web GUI and CLI — while the USW-FLEX's management spec simply reads 'Ethernet.'

For integrators who need to validate non-blocking throughput or VLAN scale in a written design, the USW-FLEX's published 10 Gbps / 5 Gbps / 7 Mpps / 1,000 VLAN figures are directly usable. The USW-FLEX-3 cannot be validated against those same parameters from the provided specs alone. Both units operate within the UniFi software ecosystem, so day-to-day management parity can be assumed at the platform level, but the USW-FLEX-3's explicit Web GUI + CLI callout confirms dual-mode access for integrators who use CLI for scripted provisioning.

Which should you choose: the USW-FLEX or the USW-FLEX-3?

Our take: The USW-FLEX is the stronger choice when the installation site lacks local AC power, requires extreme-cold operation, or demands documented switching capacity figures for design validation. Concretely: its PoE-in architecture eliminates the AC power dependency the USW-FLEX-3 carries; its operating floor of -40°C beats the USW-FLEX-3's -20°C by a full 20°C on the cold side; and its 10 Gbps switching capacity, 5 Gbps non-blocking throughput, and 1,000 VLAN support are spec-confirmed where the USW-FLEX-3's equivalents are not stated in the provided data. The USW-FLEX-3 returns a slightly higher upper temperature ceiling (60°C vs 55°C) and provides explicit Web GUI plus CLI management confirmation, which may suit hot-cabinet or CLI-provisioned deployments. Both sit in the UniFi ecosystem. Verify the USW-FLEX-3's total PoE budget directly with Ubiquiti before specifying it in high-draw-per-port scenarios.

Side-by-Side Comparison

Spec-for-spec, from manufacturer data.

Frequently Asked Questions

Related Resources

• Ubiquiti USW-FLEX product page — full specs and to add to a quote
• Ubiquiti USW-FLEX-3 product page — full specs and to add to a quote