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Computers with Allegro USB-C 4-Port PCIe Cards
SuperSpeed USB-C 10Gbps • Dual Controllers for Fast Drive-to-Drive Transfers
USB-C Charge & Sync • Four Ports with up to 7.5W Power per Port

Powerful USB 3.2 Gen 2 Performance
Add Four USB-C 10Gbps Ports to Mac Pro and Windows Computers with PCIe Slots; and Thunderbolt to PCIe Card Expansion Systems

Up to 2 Times the performance USB 3.0 and USB 3.1 Gen 1 Connections

Equipped with SSDs, the fastest USB 3.2 Gen 2 drives you can buy today are capable of 800 MB/s data transfers—many are bus-powered, too. But, most desktop computers (even new models) include generations-old USB interfaces that will throttle that performance and may not offer adequate power to allow bus-powered drives to operate. Break through the bottleneck—install Sonnet’s Allegro™ USB-C® 4-Port PCIe(1) card in your Mac Pro® or Windows® PC computer with PCIe slots; or Thunderbolt™ to PCIe card expansion system to support your fast USB drives at maximum performance.

Two Controllers, Four Ports

Featuring two 10Gbps USB 3.2 Gen 2 controllers and four USB-C ports, the Allegro PCIe card supports data transfers at up to twice as fast as USB 3.0 and USB 3.1 Gen 1 ports are capable. With two controllers onboard, the Allegro card speeds data transfers between connected drives, and enables your computer to load and off-load data more quickly.

Compatible with 2023 Mac Pro

Key Features

Four SuperSpeed USB-C 10Gbps Ports—Adds four USB-C 10Gbps ports to your Mac Pro or Windows PC computer with PCIe slots; or Thunderbolt to PCIe card expansion system

Powerful Performance with Dual USB 3.2 Gen 2 Controllers—Support data transfers at up to twice as fast as USB 3.0 and USB 3.1 Gen 1; speed data transfers between connected drives

Powered Ports—Supports USB-C bus-powered SSD, SSD RAID, and hard drive devices with up to 7.5W power per port

Protected Power Delivery—Independent power regulation isolates each port to prevent cross-coupled power glitches that may cause accidental disconnects; resettable device overcurrent fuses protect the card and computer, and may be reset by a simple shutdown

Broad USB Device Support & Compatibility—Supports storage, hubs, and other USB-IF compliant USB devices

Add USB 3.2 Gen 2 to Thunderbolt Expansion Systems—Add four SuperSpeed USB-C 10Gbps ports to Thunderbolt to PCIe card expansion systems

Supports Hot-Swappable Device Connection—Plug in and disconnect peripherals without shutting off your computer

Easy Installation—Quick and easy installation into any available PCIe slot

Power Per Port

Speed and Power

Unlike other 4-port USB cards (simple hubs that split a single USB controller’s bandwidth between all four ports), Sonnet’s Allegro PCIe card supports data transfers from a single USB 3.2 Gen 2 SSD RAID device at up to 800 MB/s— compared to using a USB 3.1 Gen 1 or USB 3.0 adapter card, transfers complete in half the time! Exploiting its dual controllers design, it’s possible to simultaneously transfer data to two connected drives at up to 660 MB/s each. With four drives connected, the four ports support simultaneous 300 MB/s transfers!

The Allegro card provides 7.5W of power through each of its ports, supporting USB bus-powered hard drives, and SSDs without the need to connect an additional AC power adapter.

Sonnet Port Power Advantages:

Unlike ordinary USB-C adapter cards, Sonnet's Allegro PCIe card was designed with a focus on intelligent power delivery and management for powering attached drives through its ports.

No Auxiliary Power Required
Ordinary USB-C cards need a separate power plug connection. Sonnet’s Allegro gets the power required to operate connected drives from the slot it’s installed in. This enables you to install the Sonnet card in any compatible computer or Thunderbolt expansion system regardless of it having extra power connectors available.

No Auxiliary Power Needed



Independent, Per-Port Power Regulation
Ordinary USB-C cards can deliver poor power regulation, allowing a connected drive to be forced off (auto-disconnected) when an additional drive is connected or disconnected. The Allegro card protects each port from power glitches on adjacent ports, preventing auto-disconnects of already-connected drives.

Resettable Fuses
Unlike ordinary USB-C cards, the Allegro card features a resettable fuse on each port, protecting both card and computer should a cable or peripheral fail. Resetting a tripped fuse is simple—just shut down and restart your computer.

Independent Power Regulation for Each Port, Resettable Fuses

Allegro USB-C 4-Port PCIe Card Ports

Easy to Access Ports

Sonnet designed the Allegro USB-C 4-Port PCIe card with custom USB-C connectors that locate the ports near the center of the PCIe bracket. Unlike other cards that use standard Type-C connectors that are mounted close to the edge of the bracket, this Allegro card provides plenty of clearance for you to plug in cables.

Add USB 3.2 to Your Thunderbolt Mac
Got a Mac with a Thunderbolt connection, but no PCIe slot? The Allegro is ideal for use in Sonnet’s Thunderbolt 2 and Thunderbolt 3 to PCIe card expansion systems, including Echo Express™ and xMac™ desktop and rackmount systems.

Mac Computers with Echo Express SE III



Perfect for the Extra Slot in Your Multi-Slot Thunderbolt System
Installing an Allegro USB-C 4-Port PCIe card in a multi-slot Thunderbolt 2 or Thunderbolt 3 to PCIe card expansion system is a great way to inexpensively add four SuperSpeed USB-C 10Gbps ports to your computer.

Easy Installation Broad Device Support

Broad Device Support, Easy Installation
The Allegro PCIe card features hot-pluggable and hot-swappable device connection support with automatic device configuration, and works with all USB-IF compliant USB peripherals. This full-height Sonnet card installs easily into any PCIe x4 (mechanical) or larger slot.

Easy Installation Broad Device Support

  Computer hardware shown in photos for illustration purposes; items sold separately.
See Tech Specs Tab for footnotes
Part No.  
USB3C-4PM-E Allegro USB-C 4-Port PCIe Card(1)
Warranty 2-year
Form Factor PCIe computer card
Bus Interface PCI Express 2.0 x4
Peripherals Supported
  • Industry standard USB 3.2 Gen 1, Gen 2 & 2x2; USB 3.1 Gen 1 & 2; USB 3.0, 2.0 and 1.1
  • Thunderbolt 3-only peripherals are NOT supported
Bus Powered Peripherals Supported
  • 1.5A per port advertised using USB Type-C Charging
  • 7.5W per port for operation or charging
Cables Supported
  • USB-C 10Gbps
  • USB-C 5Gbps (not recommended)
  • Thunderbolt 3 40Gbps (0.5-, 0.7-, 0.8-meter cables only)
  • Thunderbolt 3 20Gbps
Chipset 2x ASMedia 3142(2)
RoHS Compliant Yes
Package Contents
  • Allegro USB-C 4-Port PCIe adapter card
USB Support  
Standard Complies with OHCI (Open Host Controller Interface), EHCI (Enhanced Host Controller Interface), and xHCI (eXtensible Host Controller Interface) standards
UASP USB attached SCSI protocol supported under
macOS 10.12+, Windows 10
Alternate Modes Support No
Chipset Throughput 20Gbps combined port throughput
Number of Devices Supported Up to 62
Hot Plug Supports hot-pluggable and hot swappable device connection
Boot Support No computers support booting at this time


Specifications subject to change without notice.

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Mac Compatibility

Mac Pro® 3,1(3),  4,1,  5,1, 7,1 (2019)(4), or 14,8 (2023)(4)

macOS 10.12.6+(2)

macOS Sonoma compatible

Windows Compatibility

Computer with PCIe slots

Windows 11, 10, 8.1, 7

Windows Server 2019, 2016, 2012, and 2008 (64-bit editions)

Linux Compatibility (See Tech Note 1149)

Computer with PCIe slots

Linux Kernel 5.4.0+

Ubuntu 20.04.1+

Thunderbolt PCIe Expansion System Compatibility

Supports USB 3 devices when card is installed in a Thunderbolt to PCIe Card Expansion System

Technical Notes

  1. Product complies with USB 3.2 Gen 2 specification, which supercedes USB 3.1 Gen 2. Product package may still list USB 3.1 Gen 2.
  2. The initial version with serial number starting with “A” uses the ASMedia 1142 controller. The later versions with serial number starting with “B” and above (shipping since July 2020) use the ASMedia 3142 controller.

    USB-C Cable
  3. The maximum Apple-supported OS for the Mac Pro 3,1 is OS X 10.11. Dosdude1 offers patchers to allow installation of newer versions of macOS for the Mac Pro 3,1. The Apple USB 3 driver in these patched newer versions will support the Allegro card. Note that performance may be limited by the Mac Pro 3,1 PCIe 1.1 slot bandwidth.
  4. Cables, adapters and thumbdrives with connector overmolds > 6.5mm will not fit in the 2023 or 2019 Mac Pro PCIe backplate opening.


Mac OS logoWindows logoPCI Express LogoRoHS Compliant logo


Allegro USB-C 4-Port PCIe Product Overview (1:39 mins)

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