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Sonnet Allegro USB 3.1, Two-Port USB-C 10Gb PCIe Card (USB3C-2PM-E)
Sonnet

Sonnet Allegro USB 3.1, Two-Port USB-C 10Gb PCIe Card (USB3C-2PM-E)

Bottom line: The Sonnet Allegro USB 3.1: Two 10Gbps USB-C ports (USB 3.2 Gen 2), roughly 2x USB 3.0 throughput; main trade-off: ports are USB-C shaped but not Thunderbolt, so TB-only devices will not work.

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By , Founder & Editor-in-Chief · Listing data updated

Mike Perry — Hardware researcher since 2014. For retro PC hardware and period-correct parts, synthesises manufacturer documentation, community compatibility lists and marketplace listings rather than first-hand lab testing. Core beat: GPU performance across gaming, rendering, and local-LLM inference.

Pros & Cons

Pros

  • ✓ Two 10Gbps USB-C ports (USB 3.2 Gen 2), roughly 2x USB 3.0 throughput
  • ✓ Full 15W (3.0A) per port runs bus-powered SSDs and SSD RAID enclosures
  • ✓ Independent per-port power regulation stops cross-coupled glitches and dropouts
  • ✓ Auto-negotiates x1 on PCIe 3.0 or x2 on PCIe 2.0 for full 10Gbps either way
  • ✓ Backed by a 2-year warranty plus free lifetime support from Sonnet

Cons

  • ✗ Ports are USB-C shaped but not Thunderbolt, so TB-only devices will not work
  • ✗ Needs a free PCIe slot, ruling out laptops and slot-less small-form-factor builds
  • ✗ Windows support is listed for 11 and newer, so older Windows builds are unconfirmed

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SpecPicks Verdict

SpecPicks scored Sonnet Allegro USB 3.1 using a rating × review-volume × price-fit model applied to published specs and reviews across the expansion cards category. Sonnet's expansion cards lineup sits within the broader category mid-tier; price and specs are the deciding factors over brand loyalty here. Judge it on the specification table and the price rather than on sentiment: check the figures that decide your use case, then put it side-by-side with two or three close alternatives in the Compare tool before clicking through.

Common buyer scenarios for expansion cards of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the retailer's listing before purchase. Prices and stock are set by the retailer and may have moved since this page was last updated.

Key Features

  • SuperSpeed+ USB Technology—Adds two 10Gbps USB-C (USB 3.2 Gen 2) ports to your Mac Pro with PCIe slots, Windows PC, Linux computer, or Thunderbolt to PCIe card expansion system; transfers data up to 2x as fast as USB 3.0 connections (ports are USB3C not thunderbolt)
  • Super-Powered Ports—Supports USB-C bus-powered SSD, SSD RAID, and hard drive devices with up to 15W (3.0A) power per port
  • Protected Ports—Independent power regulation isolates each port to prevent cross-coupled power glitches that may cause accidental disconnects
  • PCIe Data Link Auto-Negotiation—Card auto-negotiates one lane data link in a PCIe 3.0 slot and two lanes in a PCIe 2.0 slot, ensuring full 10Gbps performance in either generation PCIe slot
  • Mac, Windows 11+, and Linux Compatible. 2-year warranty and free lifetime customer support since 1986

Full Specifications

BrandSonnet
StyleClassic
Style NameClassic
Unit Count1.0 Count
ConnectivityUSB-C
Model NumberUSB3C-2PM-E
CompatibilityPC, Mac, Linux
Built-In MediaSonnet Allegro Dual-Port 10Gbs USB-C (USB 3.1 Gen 2) PCIe Adapter Card with 15W
Mfr Part NumberUSB3C-2PM-E
Compatible DevicesPersonal Computer
Hardware InterfacePCI Express x16, USB 3.0 Type C, USB 3.1 Type C, USB 3.2 Gen 2, USB Type C
Warranty Description1 Year Limited Warranty
Item Dimensions L x W x H8.43"L x 5.31"W x 0.91"H
Global Trade Identification Number00732311012136

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Sonnet Allegro USB 3.1, Two-Port USB-C 10Gb PCIe Card (USB3C-2PM-E) is listed on Amazon. Price, availability, shipping and returns are set by Amazon and its sellers — check the listing for current terms. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.

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Sonnet Allegro USB 3.1, Two-Port USB-C 10Gb PCIe Card (USB3C-2PM-E)
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