Sonnet
Sonnet Allegro USB-C 4-Port PCIe Card
Bottom line: The Sonnet Allegro USB-C 4-Port PCIe Card: Four 10Gbps USB 3.2 Gen 2 ports from one PCIe slot, twice Gen 1 data rates; main trade-off: USB-C ports only, not Thunderbolt, so no eGPU or Thunderbolt dock support.
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Pros & Cons
Pros
- ✓ Four 10Gbps USB 3.2 Gen 2 ports from one PCIe slot, twice Gen 1 data rates
- ✓ Dual Gen 2 controllers split bandwidth so two drives can run fast at once
- ✓ 7.5W per port powers bus-powered USB-C SSDs and small SSD RAID enclosures
- ✓ Per-port power regulation isolates ports, cutting cross-coupled disconnect glitches
- ✓ Driverless support across macOS, Windows 11+, and Linux for mixed-OS workstations
Cons
- ✗ USB-C ports only, not Thunderbolt, so no eGPU or Thunderbolt dock support
- ✗ 149.99 USD is steep next to basic USB 3 add-in cards
- ✗ Requires a free PCIe slot, ruling out laptops and most small-form-factor builds
- ✗ No USB-A ports, so legacy peripherals need adapters or hubs
SpecPicks Verdict
SpecPicks scored Sonnet Allegro USB-C 4-Port PCIe Card 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
- 4-Port USB 3.2 Gen2 – Adds four 10Gbps USB-C ports (not Thunderbolt) to your Mac Pro or Windows PC with PCIe slots
- Dual USB 3.2 Gen 2 Controllers – Support data transfers at up to twice as fast as USB 3 Gen 1
- Powered Ports – Supports USB-C bus-powered SSD or SSD RAID with up to 7.5W per port
- Protected Power Delivery – Independent per-port power regulation isolates each port to prevent cross-coupled power glitches that may cause accidental disconnects
- Mac, Windows 11+, and Linux Compatible
Full Specifications
| Brand | Sonnet |
|---|---|
| Style | Classic |
| Style Name | Classic |
| Unit Count | 1.0 Count |
| Connectivity | USB-C |
| Model Number | USB3C-4PM-E |
| Compatibility | PC, Mac, Linux |
| Built-In Media | Sonnet Allegro USB-C 4-Port USB 3.1 Gen 2 PCIe Card with Dual 10Gb Controllers, |
| Mfr Part Number | USB3C-4PM-E |
| Compatible Devices | Personal Computer |
| Hardware Interface | PCI Express x4 |
| Warranty Description | 1 Year Limited Warranty |
| Global Trade Identification Number | 00732311012648 |
Ready to buy?
Sonnet Allegro USB-C 4-Port PCIe Card 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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